Javascript equivalent of PHP's list()

Question

Really like that function.

$matches = array('12', 'watt');
list($value, $unit) = $matches;

Is there a Javascript equivalent of that?

Answer 1

There is, in 'newer' versions of Javascript: Destructuring assignment - Javascript 1.7. It's probably only supported in Mozilla-based browsers, and maybe in Rhino.

var a = 1;  
var b = 3;  

[a, b] = [b, a];  

EDIT: actually it wouldn't surprise me if the V8 Javascript library (and thus Chrome) supports this. But don't count on it either Now supported in all modern browsers(except IE, of course).

Answer 2

try this:

matches = ['12', 'watt'];
[value, unit] = matches; 

Answer 3

ES6 does support this directly now via array destructuring.

const matches = ['12', 'watt'];
const [value, unit] = matches;

Answer 4

This is my solution for using List/Explode on Javascript. Fiddle Working Example

First the implementation :

var dateMonth = "04/15";
dateMonth.split("/").list("month","day", "year");
month == "04";
day == "15";
year == null;

It also allows for scoping the new generated variables :

var scoped = (function()
{ 
    var dateMonth = "07/24/2013"; 
    dateMonth.split("/").list("month","day", "year", this);
    this.month == "07";
    this.day == "24";
    this.year == "2013";
})();

This was accomplished by modifying an the Array prototype.

Array.prototype.list = function()
{
    var 
        limit = this.length,
        orphans = arguments.length - limit,
        scope = orphans > 0  && typeof(arguments[arguments.length-1]) != "string" ? arguments[arguments.length-1] : window 
    ;

    while(limit--) scope[arguments[limit]] = this[limit];

    if(scope != window) orphans--;

    if(orphans > 0)
    {
        orphans += this.length;
        while(orphans-- > this.length) scope[arguments[orphans]] = null;  
    }  
}

Answer 5

CoffeeScript offers destructuring assignment with the syntax:

[a, b] = someFunctionReturningAnArray()

This is pretty much identical to the feature offered in very new JavaScript versions. However, CoffeeScript produces compiled JS that is compatible even with IE6's JavaScript engine, and therefore it's a good option if compatibility is vital.

Answer 6

There is a experimental implementation of list() by PHPJS here:
https://github.com/kvz/phpjs/blob/master/_experimental/array/list.js

Answer 7

Since most JavaScript implementations don't yet support that feature, you could simply do it in a more JavaScript-like fashion:

function list(){
    var args = arguments;
    return function(array){
        var obj = {};
        for(i=0; i<args.length; i++){
            obj[args[i]] = array[i];
        }
        return obj;
    };
}

Example:

var array = ['GET', '/users', 'UserController'];
var obj = {};

obj = list('method', 'route', 'controller')(array);

console.log(obj.method);        // "GET"
console.log(obj.route);         // "/users"
console.log(obj.controller);    // "UserController"

Check the fiddle

---

An alternative is to add a list-method to Array.prototype (even I wouldn't recommend it):

Array.prototype.list = function(){
    var i, obj = {};
    for(i=0; i<arguments.length; i++){
        obj[arguments[i]] = this[i];
    }
    // if you do this, you pass to the dark side `,:,´
    this.props = obj;
    return obj;
};

Example:

/**
 * Example 1: use Array.prototype.props
 */

var array = ['GET', '/users', 'UserController'];
array.list('method', 'route', 'controller');

console.log(array.props.method);        // "GET"
console.log(array.props.route);         // "/users"
console.log(array.props.controller);    // "UserController"

/**
 * Example 2: use the return value
 */

var array = ['GET', '/users', 'UserController'];
var props = array.list('method', 'route', 'controller');

console.log(props.method);      // "GET"
console.log(props.route);       // "/users"
console.log(props.controller);  // "UserController"

Check the fiddle for that one

Answer 8

This is my hack at it; as short as I could get it without writing a function to do it. Gotta be careful of the scope of "this" though:

list = ["a","b","c"];
vals = [1,2,3];
for(var i in vals)this[list[i]]=vals[i];
console.log(a,b,c);

Good enough for a laugh. I still assign each variable one at a time:

a=vals[0];
b=vals[1];
c=vals[2];

It's much shorter this way. Besides, if you've got a bunch of variables they should probably be kept in the array, or even better they should be properties of a closure, instead of declaring them all separately.

Answer 9

function list(fn,array){
    if(fn.length && array.length){
        for(var i=0;i<array.length;i++){
            var applyArray = [];
            for(var j=0;j<array[i].length;j++){
                fn[j] = array[i][j];
                applyArray.push(fn[j]);
            }
        fn.apply(this,applyArray);
       }
   }
}

Example:

//array array mixture for composure
var arrayMixture = [ ["coffee","sugar","milk"], ["tea","sugar","honey"] ];
//call our function


list(function(treat,addin,addin2){
    console.log("I like "+treat+" with " + addin + " and " + addin2);
},arrayMixture);


//output:
//I like coffee with sugar and milk
//I like tea with sugar and honey