Find the longest string in a nested array using Recursion in Javascript?
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0
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I have seen various answers which give a solution to finding the longest string in an array. My problem is, I want to find the longest string in a nested array. The nesting level may be of N-levels or just two levels deep. My initial solution is as follows:
let myArray = [
'ABC',
'ABCD',
'ABCDE',
[
'ABC',
'ABCABABA',
[
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
function longestString(arr)
let longestStr = ''
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
longestString(item)
)
return longestStr;
console.log(longestString(myArray))
Observed Output -> ABABABABZZQ
Expected Output -> 'ABABABABABABABABAZZ'
What is the tweak needed to print only the longest string?
javascript arrays recursion
asked Nov 11 at 5:33
SeaWarrior404
62111430
add a comment |
up vote
0
down vote
favorite
I have seen various answers which give a solution to finding the longest string in an array. My problem is, I want to find the longest string in a nested array. The nesting level may be of N-levels or just two levels deep. My initial solution is as follows:
let myArray = [
'ABC',
'ABCD',
'ABCDE',
[
'ABC',
'ABCABABA',
[
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
function longestString(arr)
let longestStr = ''
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
longestString(item)
)
return longestStr;
console.log(longestString(myArray))
Observed Output -> ABABABABZZQ
Expected Output -> 'ABABABABABABABABAZZ'
What is the tweak needed to print only the longest string?
javascript arrays recursion
asked Nov 11 at 5:33
SeaWarrior404
62111430
The problem is that you are printing insidelongestString. Instead, each iteration of the function should just return the longest string found, and when calling recursively, you should compare the returned value to the current stored longest string.
– Matt
Nov 11 at 5:37
An equivalent solution to @Matt would be to pass the current longestStr as a parameter to the function so your can always compare the new strings to it. (Posted an answer here if it's not clear)
– Nirit Levi
Nov 11 at 6:49
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I have seen various answers which give a solution to finding the longest string in an array. My problem is, I want to find the longest string in a nested array. The nesting level may be of N-levels or just two levels deep. My initial solution is as follows:
let myArray = [
'ABC',
'ABCD',
'ABCDE',
[
'ABC',
'ABCABABA',
[
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
function longestString(arr)
let longestStr = ''
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
longestString(item)
)
return longestStr;
console.log(longestString(myArray))
Observed Output -> ABABABABZZQ
Expected Output -> 'ABABABABABABABABAZZ'
What is the tweak needed to print only the longest string?
javascript arrays recursion
asked Nov 11 at 5:33
SeaWarrior404
62111430
I have seen various answers which give a solution to finding the longest string in an array. My problem is, I want to find the longest string in a nested array. The nesting level may be of N-levels or just two levels deep. My initial solution is as follows:
let myArray = [
'ABC',
'ABCD',
'ABCDE',
[
'ABC',
'ABCABABA',
[
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
function longestString(arr)
let longestStr = ''
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
longestString(item)
)
return longestStr;
console.log(longestString(myArray))
Observed Output -> ABABABABZZQ
Expected Output -> 'ABABABABABABABABAZZ'
What is the tweak needed to print only the longest string?
javascript arrays recursion
javascript arrays recursion
asked Nov 11 at 5:33
SeaWarrior404
62111430
asked Nov 11 at 5:33
SeaWarrior404
62111430
asked Nov 11 at 5:33
SeaWarrior404
62111430
asked Nov 11 at 5:33
SeaWarrior404
62111430
asked Nov 11 at 5:33
SeaWarrior404
62111430
62111430
The problem is that you are printing insidelongestString. Instead, each iteration of the function should just return the longest string found, and when calling recursively, you should compare the returned value to the current stored longest string.
– Matt
Nov 11 at 5:37
An equivalent solution to @Matt would be to pass the current longestStr as a parameter to the function so your can always compare the new strings to it. (Posted an answer here if it's not clear)
– Nirit Levi
Nov 11 at 6:49
add a comment |
The problem is that you are printing insidelongestString. Instead, each iteration of the function should just return the longest string found, and when calling recursively, you should compare the returned value to the current stored longest string.
– Matt
Nov 11 at 5:37
An equivalent solution to @Matt would be to pass the current longestStr as a parameter to the function so your can always compare the new strings to it. (Posted an answer here if it's not clear)
– Nirit Levi
Nov 11 at 6:49
The problem is that you are printing inside
longestString. Instead, each iteration of the function should just return the longest string found, and when calling recursively, you should compare the returned value to the current stored longest string.– Matt
Nov 11 at 5:37
The problem is that you are printing inside
longestString. Instead, each iteration of the function should just return the longest string found, and when calling recursively, you should compare the returned value to the current stored longest string.– Matt
Nov 11 at 5:37
An equivalent solution to @Matt would be to pass the current longestStr as a parameter to the function so your can always compare the new strings to it. (Posted an answer here if it's not clear)
– Nirit Levi
Nov 11 at 6:49
An equivalent solution to @Matt would be to pass the current longestStr as a parameter to the function so your can always compare the new strings to it. (Posted an answer here if it's not clear)
– Nirit Levi
Nov 11 at 6:49
add a comment |
7 Answers
7
active
oldest
votes
up vote
1
down vote
Use Array.flat() to flatten the array, and then use Array.reduce() to find the longest item:
const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
const result = myArray
.flat(Infinity)
.reduce((r, s) => s.length > r.length ? s : r);
console.log(result);answered Nov 11 at 5:38
Ori Drori
71.4k127489
1
Problem with this method is that you are iterating the collection twice, it is quite inefficient. Not a real problem on a small data set but increases with the size of the input.
– Adrian Brand
Nov 11 at 5:45
1
This is a functional solution that splits the problem into two simple parts. Both parts are O(n), which translate to O(2n). In CS O(2n) is equivalent to O(n). This means that performance optimisation will be required only for huge arrays. In JS huge recursive solutions will fail most of the time (stack overflow).
– Ori Drori
Nov 11 at 5:55
Flat solution is what i also thought of!!!
– Nitish Narang
Nov 11 at 6:05
You do realise that flat is a recursive function? developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Adrian Brand
Nov 11 at 8:03
And flat copies the array and consumes a huge amount of memory compared to a single reduce that only keeps a single string as an accumulator. The single reduce will only consume memory for the stack to the depth of the array nesting and will fail orders of magnitude later that flat.
– Adrian Brand
Nov 11 at 8:17
|
show 2 more comments
up vote
1
down vote
You need to use the return value of the recursive call - put the returned string through the same test that you put the item through, check if it's longer than longestStr, and if so, reassign longestStr:
let myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
function longestString(arr)
let longestStr = ''
arr.forEach(item =>
if (typeof item === 'string')
if (item.length > longestStr.length)
longestStr = item;
else
const nestedLongest = longestString(item);
if (nestedLongest.length > longestStr.length)
longestStr = nestedLongest;
)
return longestStr;
console.log(longestString(myArray))Or, to be somewhat more DRY:
const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
arr.forEach(item =>
check(typeof item === 'string' ? item : longestString(item));
);
return longestStr;
console.log(longestString(myArray))Another option would be to have an inner function that gets called, while assigning to a longestStr variable that's persistently in scope until the end of the longestString function - meaning that you don't have to worry about the results of the recursive calls:
const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(input)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
function recursiveFn(arr)
arr.forEach((item) =>
if (typeof item === 'string') check(item)
else recursiveFn(item);
);
recursiveFn(input);
return longestStr;
console.log(longestString(myArray))answered Nov 11 at 5:37
CertainPerformance
67.8k143353
add a comment |
up vote
1
down vote
You can do it with a single reduce
const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
];
const findLongestStr = array => array.reduce((result, item) => typeof item === 'string' ? item.length > result ? item : result : findLongestStr(item), '');
console.log(findLongestStr(myArray));answered Nov 11 at 5:52
Adrian Brand
2,48911018
add a comment |
up vote
1
down vote
You have to declare longestStr outside the function and also you have to use the return keyword
return longestString(item)
let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
let longestStr = ''
function longestString(arr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
return longestString(item)
);
return longestStr;
console.log(longestString(myArray));EDIT - You can pass longestStr as parameter to longestString function
let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
function longestString(arr,longestStr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
var value = longestString(item,longestStr);
if(value.length > longestStr.length)
longestStr = value;
return longestStr;
);
return longestStr;
console.log(longestString(myArray,''));answered Nov 11 at 5:40
Mamun
23.2k71428
You are maintaining thelongestStrin the global context. We can passed as an argument tolongestStringitself.
– front_end_dev
Nov 11 at 5:48
add a comment |
up vote
0
down vote
Recursively call the findLongestStr if the input is Array and maintain the current maximum value.
let myArray = [
'ABC',
'ABCD',
'ABCDE',
[
'ABC',
'ABCABABA',
[
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
];
function findLongestStr(input)
return input.reduce(function(o,i)
if(i.constructor === Array)
var value = findLongestStr(i);
console.log("value array => ",value);
if(o.length < value.length)
o = value;
else
console.log("value i => ",i);
if(o.length < i.length)
o = i;
return o;
,"");
console.log("max length => ",findLongestStr(myArray));
Working jsFiddle demo - https://jsfiddle.net/k4yo35hb/1/
answered Nov 11 at 5:45
front_end_dev
1,3151511
add a comment |
up vote
0
down vote
The main problem with you code is that you redefine longestStr each time the recursive function is called. Leaving you no way of comparing the longest string from each recursive call.
Using reduce() is a nice way to find the max of a regular un-nested array. You can add a little bit of recursion and still use reduce() for this which takes care of maintaining state between recursions because all the recursion unwinds within the reduce function:
let myArray = ['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
return arr.reduce((longest, item) =>
if (Array.isArray(item))
let rec = longestString(item)
if (rec.length > longest.length) longest = rec
else if (item.length > longest.length) longest = item;
return longest
, '')
console.log(longestString(myArray))answered Nov 11 at 5:56
Mark Meyer
30.7k32550
Without providing the default intial value inreducefunction it's getting undefined inlongestat first place.
– front_end_dev
Nov 11 at 6:08
1
If you don't define the initial accumulator in a reduce function it uses the first element of the array, not undefined. In this case you need to define the accumulator as an empty string just incase the first item is an array.
– Adrian Brand
Nov 11 at 8:12
add a comment |
up vote
0
down vote
with respect to @Adrian Brand clean answer, here is the solution:
const findMaxStringInArray = (array, lastMax = '' ) => array.reduce((curMax,item)=>typeof item === 'string'? item.length > curMax.length? item : curMax : findMaxStringInArray(item, curMax) ,lastMax);
answered Nov 11 at 6:40
Nirit Levi
2017
add a comment |
7 Answers
7
active
oldest
votes
7 Answers
7
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
Use Array.flat() to flatten the array, and then use Array.reduce() to find the longest item:
const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
const result = myArray
.flat(Infinity)
.reduce((r, s) => s.length > r.length ? s : r);
console.log(result);answered Nov 11 at 5:38
Ori Drori
71.4k127489
1
Problem with this method is that you are iterating the collection twice, it is quite inefficient. Not a real problem on a small data set but increases with the size of the input.
– Adrian Brand
Nov 11 at 5:45
1
This is a functional solution that splits the problem into two simple parts. Both parts are O(n), which translate to O(2n). In CS O(2n) is equivalent to O(n). This means that performance optimisation will be required only for huge arrays. In JS huge recursive solutions will fail most of the time (stack overflow).
– Ori Drori
Nov 11 at 5:55
Flat solution is what i also thought of!!!
– Nitish Narang
Nov 11 at 6:05
You do realise that flat is a recursive function? developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Adrian Brand
Nov 11 at 8:03
And flat copies the array and consumes a huge amount of memory compared to a single reduce that only keeps a single string as an accumulator. The single reduce will only consume memory for the stack to the depth of the array nesting and will fail orders of magnitude later that flat.
– Adrian Brand
Nov 11 at 8:17
|
show 2 more comments
up vote
1
down vote
Use Array.flat() to flatten the array, and then use Array.reduce() to find the longest item:
const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
const result = myArray
.flat(Infinity)
.reduce((r, s) => s.length > r.length ? s : r);
console.log(result);answered Nov 11 at 5:38
Ori Drori
71.4k127489
1
Problem with this method is that you are iterating the collection twice, it is quite inefficient. Not a real problem on a small data set but increases with the size of the input.
– Adrian Brand
Nov 11 at 5:45
1
This is a functional solution that splits the problem into two simple parts. Both parts are O(n), which translate to O(2n). In CS O(2n) is equivalent to O(n). This means that performance optimisation will be required only for huge arrays. In JS huge recursive solutions will fail most of the time (stack overflow).
– Ori Drori
Nov 11 at 5:55
Flat solution is what i also thought of!!!
– Nitish Narang
Nov 11 at 6:05
You do realise that flat is a recursive function? developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Adrian Brand
Nov 11 at 8:03
And flat copies the array and consumes a huge amount of memory compared to a single reduce that only keeps a single string as an accumulator. The single reduce will only consume memory for the stack to the depth of the array nesting and will fail orders of magnitude later that flat.
– Adrian Brand
Nov 11 at 8:17
|
show 2 more comments
up vote
1
down vote
up vote
1
down vote
Use Array.flat() to flatten the array, and then use Array.reduce() to find the longest item:
const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
const result = myArray
.flat(Infinity)
.reduce((r, s) => s.length > r.length ? s : r);
console.log(result);answered Nov 11 at 5:38
Ori Drori
71.4k127489
Use Array.flat() to flatten the array, and then use Array.reduce() to find the longest item:
const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
const result = myArray
.flat(Infinity)
.reduce((r, s) => s.length > r.length ? s : r);
console.log(result);const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
const result = myArray
.flat(Infinity)
.reduce((r, s) => s.length > r.length ? s : r);
console.log(result);const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
const result = myArray
.flat(Infinity)
.reduce((r, s) => s.length > r.length ? s : r);
console.log(result);answered Nov 11 at 5:38
Ori Drori
71.4k127489
answered Nov 11 at 5:38
Ori Drori
71.4k127489
answered Nov 11 at 5:38
Ori Drori
71.4k127489
answered Nov 11 at 5:38
Ori Drori
71.4k127489
71.4k127489
1
Problem with this method is that you are iterating the collection twice, it is quite inefficient. Not a real problem on a small data set but increases with the size of the input.
– Adrian Brand
Nov 11 at 5:45
1
This is a functional solution that splits the problem into two simple parts. Both parts are O(n), which translate to O(2n). In CS O(2n) is equivalent to O(n). This means that performance optimisation will be required only for huge arrays. In JS huge recursive solutions will fail most of the time (stack overflow).
– Ori Drori
Nov 11 at 5:55
Flat solution is what i also thought of!!!
– Nitish Narang
Nov 11 at 6:05
You do realise that flat is a recursive function? developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Adrian Brand
Nov 11 at 8:03
And flat copies the array and consumes a huge amount of memory compared to a single reduce that only keeps a single string as an accumulator. The single reduce will only consume memory for the stack to the depth of the array nesting and will fail orders of magnitude later that flat.
– Adrian Brand
Nov 11 at 8:17
|
show 2 more comments
1
Problem with this method is that you are iterating the collection twice, it is quite inefficient. Not a real problem on a small data set but increases with the size of the input.
– Adrian Brand
Nov 11 at 5:45
1
This is a functional solution that splits the problem into two simple parts. Both parts are O(n), which translate to O(2n). In CS O(2n) is equivalent to O(n). This means that performance optimisation will be required only for huge arrays. In JS huge recursive solutions will fail most of the time (stack overflow).
– Ori Drori
Nov 11 at 5:55
Flat solution is what i also thought of!!!
– Nitish Narang
Nov 11 at 6:05
You do realise that flat is a recursive function? developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Adrian Brand
Nov 11 at 8:03
And flat copies the array and consumes a huge amount of memory compared to a single reduce that only keeps a single string as an accumulator. The single reduce will only consume memory for the stack to the depth of the array nesting and will fail orders of magnitude later that flat.
– Adrian Brand
Nov 11 at 8:17
1
1
Problem with this method is that you are iterating the collection twice, it is quite inefficient. Not a real problem on a small data set but increases with the size of the input.
– Adrian Brand
Nov 11 at 5:45
Problem with this method is that you are iterating the collection twice, it is quite inefficient. Not a real problem on a small data set but increases with the size of the input.
– Adrian Brand
Nov 11 at 5:45
1
1
This is a functional solution that splits the problem into two simple parts. Both parts are O(n), which translate to O(2n). In CS O(2n) is equivalent to O(n). This means that performance optimisation will be required only for huge arrays. In JS huge recursive solutions will fail most of the time (stack overflow).
– Ori Drori
Nov 11 at 5:55
This is a functional solution that splits the problem into two simple parts. Both parts are O(n), which translate to O(2n). In CS O(2n) is equivalent to O(n). This means that performance optimisation will be required only for huge arrays. In JS huge recursive solutions will fail most of the time (stack overflow).
– Ori Drori
Nov 11 at 5:55
Flat solution is what i also thought of!!!
– Nitish Narang
Nov 11 at 6:05
Flat solution is what i also thought of!!!
– Nitish Narang
Nov 11 at 6:05
You do realise that flat is a recursive function? developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Adrian Brand
Nov 11 at 8:03
You do realise that flat is a recursive function? developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
– Adrian Brand
Nov 11 at 8:03
And flat copies the array and consumes a huge amount of memory compared to a single reduce that only keeps a single string as an accumulator. The single reduce will only consume memory for the stack to the depth of the array nesting and will fail orders of magnitude later that flat.
– Adrian Brand
Nov 11 at 8:17
And flat copies the array and consumes a huge amount of memory compared to a single reduce that only keeps a single string as an accumulator. The single reduce will only consume memory for the stack to the depth of the array nesting and will fail orders of magnitude later that flat.
– Adrian Brand
Nov 11 at 8:17
|
show 2 more comments
up vote
1
down vote
You need to use the return value of the recursive call - put the returned string through the same test that you put the item through, check if it's longer than longestStr, and if so, reassign longestStr:
let myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
function longestString(arr)
let longestStr = ''
arr.forEach(item =>
if (typeof item === 'string')
if (item.length > longestStr.length)
longestStr = item;
else
const nestedLongest = longestString(item);
if (nestedLongest.length > longestStr.length)
longestStr = nestedLongest;
)
return longestStr;
console.log(longestString(myArray))Or, to be somewhat more DRY:
const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
arr.forEach(item =>
check(typeof item === 'string' ? item : longestString(item));
);
return longestStr;
console.log(longestString(myArray))Another option would be to have an inner function that gets called, while assigning to a longestStr variable that's persistently in scope until the end of the longestString function - meaning that you don't have to worry about the results of the recursive calls:
const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(input)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
function recursiveFn(arr)
arr.forEach((item) =>
if (typeof item === 'string') check(item)
else recursiveFn(item);
);
recursiveFn(input);
return longestStr;
console.log(longestString(myArray))answered Nov 11 at 5:37
CertainPerformance
67.8k143353
add a comment |
up vote
1
down vote
You need to use the return value of the recursive call - put the returned string through the same test that you put the item through, check if it's longer than longestStr, and if so, reassign longestStr:
let myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
function longestString(arr)
let longestStr = ''
arr.forEach(item =>
if (typeof item === 'string')
if (item.length > longestStr.length)
longestStr = item;
else
const nestedLongest = longestString(item);
if (nestedLongest.length > longestStr.length)
longestStr = nestedLongest;
)
return longestStr;
console.log(longestString(myArray))Or, to be somewhat more DRY:
const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
arr.forEach(item =>
check(typeof item === 'string' ? item : longestString(item));
);
return longestStr;
console.log(longestString(myArray))Another option would be to have an inner function that gets called, while assigning to a longestStr variable that's persistently in scope until the end of the longestString function - meaning that you don't have to worry about the results of the recursive calls:
const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(input)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
function recursiveFn(arr)
arr.forEach((item) =>
if (typeof item === 'string') check(item)
else recursiveFn(item);
);
recursiveFn(input);
return longestStr;
console.log(longestString(myArray))answered Nov 11 at 5:37
CertainPerformance
67.8k143353
add a comment |
up vote
1
down vote
up vote
1
down vote
You need to use the return value of the recursive call - put the returned string through the same test that you put the item through, check if it's longer than longestStr, and if so, reassign longestStr:
let myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
function longestString(arr)
let longestStr = ''
arr.forEach(item =>
if (typeof item === 'string')
if (item.length > longestStr.length)
longestStr = item;
else
const nestedLongest = longestString(item);
if (nestedLongest.length > longestStr.length)
longestStr = nestedLongest;
)
return longestStr;
console.log(longestString(myArray))Or, to be somewhat more DRY:
const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
arr.forEach(item =>
check(typeof item === 'string' ? item : longestString(item));
);
return longestStr;
console.log(longestString(myArray))Another option would be to have an inner function that gets called, while assigning to a longestStr variable that's persistently in scope until the end of the longestString function - meaning that you don't have to worry about the results of the recursive calls:
const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(input)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
function recursiveFn(arr)
arr.forEach((item) =>
if (typeof item === 'string') check(item)
else recursiveFn(item);
);
recursiveFn(input);
return longestStr;
console.log(longestString(myArray))answered Nov 11 at 5:37
CertainPerformance
67.8k143353
You need to use the return value of the recursive call - put the returned string through the same test that you put the item through, check if it's longer than longestStr, and if so, reassign longestStr:
let myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
function longestString(arr)
let longestStr = ''
arr.forEach(item =>
if (typeof item === 'string')
if (item.length > longestStr.length)
longestStr = item;
else
const nestedLongest = longestString(item);
if (nestedLongest.length > longestStr.length)
longestStr = nestedLongest;
)
return longestStr;
console.log(longestString(myArray))Or, to be somewhat more DRY:
const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
arr.forEach(item =>
check(typeof item === 'string' ? item : longestString(item));
);
return longestStr;
console.log(longestString(myArray))Another option would be to have an inner function that gets called, while assigning to a longestStr variable that's persistently in scope until the end of the longestString function - meaning that you don't have to worry about the results of the recursive calls:
const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(input)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
function recursiveFn(arr)
arr.forEach((item) =>
if (typeof item === 'string') check(item)
else recursiveFn(item);
);
recursiveFn(input);
return longestStr;
console.log(longestString(myArray))let myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
function longestString(arr)
let longestStr = ''
arr.forEach(item =>
if (typeof item === 'string')
if (item.length > longestStr.length)
longestStr = item;
else
const nestedLongest = longestString(item);
if (nestedLongest.length > longestStr.length)
longestStr = nestedLongest;
)
return longestStr;
console.log(longestString(myArray))let myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
]
function longestString(arr)
let longestStr = ''
arr.forEach(item =>
if (typeof item === 'string')
if (item.length > longestStr.length)
longestStr = item;
else
const nestedLongest = longestString(item);
if (nestedLongest.length > longestStr.length)
longestStr = nestedLongest;
)
return longestStr;
console.log(longestString(myArray))const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
arr.forEach(item =>
check(typeof item === 'string' ? item : longestString(item));
);
return longestStr;
console.log(longestString(myArray))const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
arr.forEach(item =>
check(typeof item === 'string' ? item : longestString(item));
);
return longestStr;
console.log(longestString(myArray))const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(input)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
function recursiveFn(arr)
arr.forEach((item) =>
if (typeof item === 'string') check(item)
else recursiveFn(item);
);
recursiveFn(input);
return longestStr;
console.log(longestString(myArray))const myArray=['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(input)
let longestStr = '';
const check = str =>
if (str.length > longestStr.length) longestStr = str;
;
function recursiveFn(arr)
arr.forEach((item) =>
if (typeof item === 'string') check(item)
else recursiveFn(item);
);
recursiveFn(input);
return longestStr;
console.log(longestString(myArray))answered Nov 11 at 5:37
CertainPerformance
67.8k143353
edited Nov 11 at 5:46
answered Nov 11 at 5:37
CertainPerformance
67.8k143353
answered Nov 11 at 5:37
CertainPerformance
67.8k143353
answered Nov 11 at 5:37
CertainPerformance
67.8k143353
67.8k143353
add a comment |
add a comment |
up vote
1
down vote
You can do it with a single reduce
const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
];
const findLongestStr = array => array.reduce((result, item) => typeof item === 'string' ? item.length > result ? item : result : findLongestStr(item), '');
console.log(findLongestStr(myArray));answered Nov 11 at 5:52
Adrian Brand
2,48911018
add a comment |
up vote
1
down vote
You can do it with a single reduce
const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
];
const findLongestStr = array => array.reduce((result, item) => typeof item === 'string' ? item.length > result ? item : result : findLongestStr(item), '');
console.log(findLongestStr(myArray));answered Nov 11 at 5:52
Adrian Brand
2,48911018
add a comment |
up vote
1
down vote
up vote
1
down vote
You can do it with a single reduce
const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
];
const findLongestStr = array => array.reduce((result, item) => typeof item === 'string' ? item.length > result ? item : result : findLongestStr(item), '');
console.log(findLongestStr(myArray));answered Nov 11 at 5:52
Adrian Brand
2,48911018
You can do it with a single reduce
const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
];
const findLongestStr = array => array.reduce((result, item) => typeof item === 'string' ? item.length > result ? item : result : findLongestStr(item), '');
console.log(findLongestStr(myArray));const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
];
const findLongestStr = array => array.reduce((result, item) => typeof item === 'string' ? item.length > result ? item : result : findLongestStr(item), '');
console.log(findLongestStr(myArray));const myArray = [
'ABC',
'ABCD',
'ABCDE', [
'ABC',
'ABCABABA', [
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
];
const findLongestStr = array => array.reduce((result, item) => typeof item === 'string' ? item.length > result ? item : result : findLongestStr(item), '');
console.log(findLongestStr(myArray));answered Nov 11 at 5:52
Adrian Brand
2,48911018
answered Nov 11 at 5:52
Adrian Brand
2,48911018
answered Nov 11 at 5:52
Adrian Brand
2,48911018
answered Nov 11 at 5:52
Adrian Brand
2,48911018
2,48911018
add a comment |
add a comment |
up vote
1
down vote
You have to declare longestStr outside the function and also you have to use the return keyword
return longestString(item)
let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
let longestStr = ''
function longestString(arr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
return longestString(item)
);
return longestStr;
console.log(longestString(myArray));EDIT - You can pass longestStr as parameter to longestString function
let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
function longestString(arr,longestStr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
var value = longestString(item,longestStr);
if(value.length > longestStr.length)
longestStr = value;
return longestStr;
);
return longestStr;
console.log(longestString(myArray,''));answered Nov 11 at 5:40
Mamun
23.2k71428
You are maintaining thelongestStrin the global context. We can passed as an argument tolongestStringitself.
– front_end_dev
Nov 11 at 5:48
add a comment |
up vote
1
down vote
You have to declare longestStr outside the function and also you have to use the return keyword
return longestString(item)
let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
let longestStr = ''
function longestString(arr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
return longestString(item)
);
return longestStr;
console.log(longestString(myArray));EDIT - You can pass longestStr as parameter to longestString function
let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
function longestString(arr,longestStr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
var value = longestString(item,longestStr);
if(value.length > longestStr.length)
longestStr = value;
return longestStr;
);
return longestStr;
console.log(longestString(myArray,''));answered Nov 11 at 5:40
Mamun
23.2k71428
You are maintaining thelongestStrin the global context. We can passed as an argument tolongestStringitself.
– front_end_dev
Nov 11 at 5:48
add a comment |
up vote
1
down vote
up vote
1
down vote
You have to declare longestStr outside the function and also you have to use the return keyword
return longestString(item)
let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
let longestStr = ''
function longestString(arr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
return longestString(item)
);
return longestStr;
console.log(longestString(myArray));EDIT - You can pass longestStr as parameter to longestString function
let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
function longestString(arr,longestStr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
var value = longestString(item,longestStr);
if(value.length > longestStr.length)
longestStr = value;
return longestStr;
);
return longestStr;
console.log(longestString(myArray,''));answered Nov 11 at 5:40
Mamun
23.2k71428
You have to declare longestStr outside the function and also you have to use the return keyword
return longestString(item)
let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
let longestStr = ''
function longestString(arr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
return longestString(item)
);
return longestStr;
console.log(longestString(myArray));EDIT - You can pass longestStr as parameter to longestString function
let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
function longestString(arr,longestStr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
var value = longestString(item,longestStr);
if(value.length > longestStr.length)
longestStr = value;
return longestStr;
);
return longestStr;
console.log(longestString(myArray,''));let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
let longestStr = ''
function longestString(arr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
return longestString(item)
);
return longestStr;
console.log(longestString(myArray));let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
let longestStr = ''
function longestString(arr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
return longestString(item)
);
return longestStr;
console.log(longestString(myArray));let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
function longestString(arr,longestStr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
var value = longestString(item,longestStr);
if(value.length > longestStr.length)
longestStr = value;
return longestStr;
);
return longestStr;
console.log(longestString(myArray,''));let myArray = [['ABC','ABCD','ABCDE',
['ABC','ABCABABA',
['ABABABABABABABABAZZ'],
'ABCABABASS'],
'ABCDEFGH',
'ABABABABZZQ']]
function longestString(arr,longestStr)
arr.forEach(item =>
if(typeof item === 'string')
if(item.length > longestStr.length)
longestStr = item;
console.log('Longest Item', item);
else
var value = longestString(item,longestStr);
if(value.length > longestStr.length)
longestStr = value;
return longestStr;
);
return longestStr;
console.log(longestString(myArray,''));answered Nov 11 at 5:40
Mamun
23.2k71428
edited Nov 11 at 5:59
answered Nov 11 at 5:40
Mamun
23.2k71428
answered Nov 11 at 5:40
Mamun
23.2k71428
answered Nov 11 at 5:40
Mamun
23.2k71428
23.2k71428
You are maintaining thelongestStrin the global context. We can passed as an argument tolongestStringitself.
– front_end_dev
Nov 11 at 5:48
add a comment |
You are maintaining thelongestStrin the global context. We can passed as an argument tolongestStringitself.
– front_end_dev
Nov 11 at 5:48
You are maintaining the
longestStr in the global context. We can passed as an argument to longestString itself.– front_end_dev
Nov 11 at 5:48
You are maintaining the
longestStr in the global context. We can passed as an argument to longestString itself.– front_end_dev
Nov 11 at 5:48
add a comment |
up vote
0
down vote
Recursively call the findLongestStr if the input is Array and maintain the current maximum value.
let myArray = [
'ABC',
'ABCD',
'ABCDE',
[
'ABC',
'ABCABABA',
[
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
];
function findLongestStr(input)
return input.reduce(function(o,i)
if(i.constructor === Array)
var value = findLongestStr(i);
console.log("value array => ",value);
if(o.length < value.length)
o = value;
else
console.log("value i => ",i);
if(o.length < i.length)
o = i;
return o;
,"");
console.log("max length => ",findLongestStr(myArray));
Working jsFiddle demo - https://jsfiddle.net/k4yo35hb/1/
answered Nov 11 at 5:45
front_end_dev
1,3151511
add a comment |
up vote
0
down vote
Recursively call the findLongestStr if the input is Array and maintain the current maximum value.
let myArray = [
'ABC',
'ABCD',
'ABCDE',
[
'ABC',
'ABCABABA',
[
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
];
function findLongestStr(input)
return input.reduce(function(o,i)
if(i.constructor === Array)
var value = findLongestStr(i);
console.log("value array => ",value);
if(o.length < value.length)
o = value;
else
console.log("value i => ",i);
if(o.length < i.length)
o = i;
return o;
,"");
console.log("max length => ",findLongestStr(myArray));
Working jsFiddle demo - https://jsfiddle.net/k4yo35hb/1/
answered Nov 11 at 5:45
front_end_dev
1,3151511
add a comment |
up vote
0
down vote
up vote
0
down vote
Recursively call the findLongestStr if the input is Array and maintain the current maximum value.
let myArray = [
'ABC',
'ABCD',
'ABCDE',
[
'ABC',
'ABCABABA',
[
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
];
function findLongestStr(input)
return input.reduce(function(o,i)
if(i.constructor === Array)
var value = findLongestStr(i);
console.log("value array => ",value);
if(o.length < value.length)
o = value;
else
console.log("value i => ",i);
if(o.length < i.length)
o = i;
return o;
,"");
console.log("max length => ",findLongestStr(myArray));
Working jsFiddle demo - https://jsfiddle.net/k4yo35hb/1/
answered Nov 11 at 5:45
front_end_dev
1,3151511
Recursively call the findLongestStr if the input is Array and maintain the current maximum value.
let myArray = [
'ABC',
'ABCD',
'ABCDE',
[
'ABC',
'ABCABABA',
[
'ABABABABABABABABAZZ'
],
'ABCABABASS',
],
'ABCDEFGH',
'ABABABABZZQ'
];
function findLongestStr(input)
return input.reduce(function(o,i)
if(i.constructor === Array)
var value = findLongestStr(i);
console.log("value array => ",value);
if(o.length < value.length)
o = value;
else
console.log("value i => ",i);
if(o.length < i.length)
o = i;
return o;
,"");
console.log("max length => ",findLongestStr(myArray));
Working jsFiddle demo - https://jsfiddle.net/k4yo35hb/1/
answered Nov 11 at 5:45
front_end_dev
1,3151511
answered Nov 11 at 5:45
front_end_dev
1,3151511
answered Nov 11 at 5:45
front_end_dev
1,3151511
answered Nov 11 at 5:45
front_end_dev
1,3151511
1,3151511
add a comment |
add a comment |
up vote
0
down vote
The main problem with you code is that you redefine longestStr each time the recursive function is called. Leaving you no way of comparing the longest string from each recursive call.
Using reduce() is a nice way to find the max of a regular un-nested array. You can add a little bit of recursion and still use reduce() for this which takes care of maintaining state between recursions because all the recursion unwinds within the reduce function:
let myArray = ['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
return arr.reduce((longest, item) =>
if (Array.isArray(item))
let rec = longestString(item)
if (rec.length > longest.length) longest = rec
else if (item.length > longest.length) longest = item;
return longest
, '')
console.log(longestString(myArray))answered Nov 11 at 5:56
Mark Meyer
30.7k32550
Without providing the default intial value inreducefunction it's getting undefined inlongestat first place.
– front_end_dev
Nov 11 at 6:08
1
If you don't define the initial accumulator in a reduce function it uses the first element of the array, not undefined. In this case you need to define the accumulator as an empty string just incase the first item is an array.
– Adrian Brand
Nov 11 at 8:12
add a comment |
up vote
0
down vote
The main problem with you code is that you redefine longestStr each time the recursive function is called. Leaving you no way of comparing the longest string from each recursive call.
Using reduce() is a nice way to find the max of a regular un-nested array. You can add a little bit of recursion and still use reduce() for this which takes care of maintaining state between recursions because all the recursion unwinds within the reduce function:
let myArray = ['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
return arr.reduce((longest, item) =>
if (Array.isArray(item))
let rec = longestString(item)
if (rec.length > longest.length) longest = rec
else if (item.length > longest.length) longest = item;
return longest
, '')
console.log(longestString(myArray))answered Nov 11 at 5:56
Mark Meyer
30.7k32550
Without providing the default intial value inreducefunction it's getting undefined inlongestat first place.
– front_end_dev
Nov 11 at 6:08
1
If you don't define the initial accumulator in a reduce function it uses the first element of the array, not undefined. In this case you need to define the accumulator as an empty string just incase the first item is an array.
– Adrian Brand
Nov 11 at 8:12
add a comment |
up vote
0
down vote
up vote
0
down vote
The main problem with you code is that you redefine longestStr each time the recursive function is called. Leaving you no way of comparing the longest string from each recursive call.
Using reduce() is a nice way to find the max of a regular un-nested array. You can add a little bit of recursion and still use reduce() for this which takes care of maintaining state between recursions because all the recursion unwinds within the reduce function:
let myArray = ['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
return arr.reduce((longest, item) =>
if (Array.isArray(item))
let rec = longestString(item)
if (rec.length > longest.length) longest = rec
else if (item.length > longest.length) longest = item;
return longest
, '')
console.log(longestString(myArray))answered Nov 11 at 5:56
Mark Meyer
30.7k32550
The main problem with you code is that you redefine longestStr each time the recursive function is called. Leaving you no way of comparing the longest string from each recursive call.
Using reduce() is a nice way to find the max of a regular un-nested array. You can add a little bit of recursion and still use reduce() for this which takes care of maintaining state between recursions because all the recursion unwinds within the reduce function:
let myArray = ['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
return arr.reduce((longest, item) =>
if (Array.isArray(item))
let rec = longestString(item)
if (rec.length > longest.length) longest = rec
else if (item.length > longest.length) longest = item;
return longest
, '')
console.log(longestString(myArray))let myArray = ['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
return arr.reduce((longest, item) =>
if (Array.isArray(item))
let rec = longestString(item)
if (rec.length > longest.length) longest = rec
else if (item.length > longest.length) longest = item;
return longest
, '')
console.log(longestString(myArray))let myArray = ['ABC','ABCD','ABCDE',['ABC','ABCABABA',['ABABABABABABABABAZZ'],'ABCABABASS',],'ABCDEFGH','ABABABABZZQ']
function longestString(arr)
return arr.reduce((longest, item) =>
if (Array.isArray(item))
let rec = longestString(item)
if (rec.length > longest.length) longest = rec
else if (item.length > longest.length) longest = item;
return longest
, '')
console.log(longestString(myArray))answered Nov 11 at 5:56
Mark Meyer
30.7k32550
edited Nov 11 at 6:11
answered Nov 11 at 5:56
Mark Meyer
30.7k32550
answered Nov 11 at 5:56
Mark Meyer
30.7k32550
answered Nov 11 at 5:56
Mark Meyer
30.7k32550
30.7k32550
Without providing the default intial value inreducefunction it's getting undefined inlongestat first place.
– front_end_dev
Nov 11 at 6:08
1
If you don't define the initial accumulator in a reduce function it uses the first element of the array, not undefined. In this case you need to define the accumulator as an empty string just incase the first item is an array.
– Adrian Brand
Nov 11 at 8:12
add a comment |
Without providing the default intial value inreducefunction it's getting undefined inlongestat first place.
– front_end_dev
Nov 11 at 6:08
1
If you don't define the initial accumulator in a reduce function it uses the first element of the array, not undefined. In this case you need to define the accumulator as an empty string just incase the first item is an array.
– Adrian Brand
Nov 11 at 8:12
Without providing the default intial value in
reduce function it's getting undefined in longest at first place.– front_end_dev
Nov 11 at 6:08
Without providing the default intial value in
reduce function it's getting undefined in longest at first place.– front_end_dev
Nov 11 at 6:08
1
1
If you don't define the initial accumulator in a reduce function it uses the first element of the array, not undefined. In this case you need to define the accumulator as an empty string just incase the first item is an array.
– Adrian Brand
Nov 11 at 8:12
If you don't define the initial accumulator in a reduce function it uses the first element of the array, not undefined. In this case you need to define the accumulator as an empty string just incase the first item is an array.
– Adrian Brand
Nov 11 at 8:12
add a comment |
up vote
0
down vote
with respect to @Adrian Brand clean answer, here is the solution:
const findMaxStringInArray = (array, lastMax = '' ) => array.reduce((curMax,item)=>typeof item === 'string'? item.length > curMax.length? item : curMax : findMaxStringInArray(item, curMax) ,lastMax);
answered Nov 11 at 6:40
Nirit Levi
2017
add a comment |
up vote
0
down vote
with respect to @Adrian Brand clean answer, here is the solution:
const findMaxStringInArray = (array, lastMax = '' ) => array.reduce((curMax,item)=>typeof item === 'string'? item.length > curMax.length? item : curMax : findMaxStringInArray(item, curMax) ,lastMax);
answered Nov 11 at 6:40
Nirit Levi
2017
add a comment |
up vote
0
down vote
up vote
0
down vote
with respect to @Adrian Brand clean answer, here is the solution:
const findMaxStringInArray = (array, lastMax = '' ) => array.reduce((curMax,item)=>typeof item === 'string'? item.length > curMax.length? item : curMax : findMaxStringInArray(item, curMax) ,lastMax);
answered Nov 11 at 6:40
Nirit Levi
2017
with respect to @Adrian Brand clean answer, here is the solution:
const findMaxStringInArray = (array, lastMax = '' ) => array.reduce((curMax,item)=>typeof item === 'string'? item.length > curMax.length? item : curMax : findMaxStringInArray(item, curMax) ,lastMax);
answered Nov 11 at 6:40
Nirit Levi
2017
answered Nov 11 at 6:40
Nirit Levi
2017
answered Nov 11 at 6:40
Nirit Levi
2017
answered Nov 11 at 6:40
Nirit Levi
2017
2017
add a comment |
add a comment |
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The problem is that you are printing inside
longestString. Instead, each iteration of the function should just return the longest string found, and when calling recursively, you should compare the returned value to the current stored longest string.– Matt
Nov 11 at 5:37
An equivalent solution to @Matt would be to pass the current longestStr as a parameter to the function so your can always compare the new strings to it. (Posted an answer here if it's not clear)
– Nirit Levi
Nov 11 at 6:49