Myujth

Is there a way to retain the name of a destructured function argument? I.e., the name of the root object?

In ES5, I might do this (using inheritance as a metaphor to make the point):

// ES5:
var setupParentClass5 = function(options) 
 textEditor.setup(options.rows, options.columns);
;

var setupChildClass5 = function(options) 
 rangeSlider.setup(options.minVal, options.maxVal);
 setupParentClass5(options); // <= we pass the options object UP
;

I'm using the same options object to hold multiple configuration parameters. Some parameters are used by the parent class, and some are used by the subclass.

Is there a way to do this with destructured function arguments in ES6?

// ES6:
var setupParentClass6 = (rows, columns) => 
 textEditor.setup(rows, columns);
;

var setupChildClass6 = (minVal, maxVal) => 
 rangeSlider.setup(minVal, maxVal);
 setupParentClass6( /* ??? */ ); // how to pass the root options object?
;

Or do I need to extract all of the options in setupChildClass6() so that they can be individually passed into setupParentClass6()?

// ugh.
var setupChildClass6b = (minVal, maxVal, rows, columns) => 
 rangeSlider.setup(minVal, maxVal);
 setupParentClass6(rows, columns);
;

I have the 'options' arguments on too many places myself. I would opt for 1 extra line of code. Not worthy in this example, but a good solution when having destructuring on more lines.

const setupChildClass6 = options => 
 const minVal, maxVal = options;
 rangeSlider.setup(minVal, maxVal);
 setupParentClass6(options); 
;

You cannot do it directly in the arguments, but you can extract the values afterward:

function myFun(allVals) 
 const val1, val2, val3 = allVals;
 console.log("easy access to individual entries:", val2);
 console.log("easy access to all entries:", allVals);

You cannot use destructuring and simple named positional argument for the same parameter at the same time. What you can do:

1. 
   

   Use destructuring for setupParentClass6 function, but old ES6 approach for setupChildClass6 (I think this is the best choice, just make name shorter):

   
   
   

   var setupChildClass6 = (o) => 
    rangeSlider.setup(o.minVal, o.maxVal);
    setupParentClass6(o); 
   ;
   

   
   


2. 
   

   Use old arguments object. But arguments can slow down a function (V8 particular), so I think it's a bad approach:

   
   
   

   var setupChildClass6 = (minVal, maxVal) => 
    rangeSlider.setup(minVal, maxVal);
    setupParentClass6(arguments[0]); 
   ;
   

   
   


3. 
   

   ES7 has proposal for rest/spread properties (if you don't need minVal and maxVal in setupParentCalss6 function):

   
   
   

   var setupChildClass6b = (minVal, maxVal, ...rest) => 
    rangeSlider.setup(minVal, maxVal);
    setupParentClass6(rest);
   ;
   

   
   
   

   Unfortunately it's not ES6.