Rplus/Spread Operator.md

## Spread Operator.md

      
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              Spread Operator.md
            
          
    Calling Functions without Apply

function doStuff (x, y, z) { }
var args = [0, 1, 2];
doStuff(...args);

function doStuff(x, y, z) {}
var args = [0, 1, 2];
doStuff.apply(undefined, args);


Combine Arrays

var arr1 = ['two', 'three'];
var arr2 = ['one', ...arr1, 'four', 'five'];

var arr1 = ['two', 'three'];
var arr2 = ['one'].concat(arr1, ['four', 'five']);


arr1.push(...arr2) // Adds arr2 items to end of array
arr1.unshift(...arr2) //Adds arr2 items to beginning of array

arr1.push.apply(arr1, arr2);
arr1.unshift.apply(arr1, arr2);


Copying Arrays

var arr = [1, 2, 3];
var arr2 = [...arr]; // like arr.slice()
arr2.push(4);

var arr = [1, 2, 3];
var arr2 = [].concat(arr);
arr2.push(4);


Convert arguments or NodeList to Array

[...document.querySelectorAll('div')];

[].concat(document.querySelectorAll('div'));


Using Math Functions

let numbers = [9, 4, 7, 1];
Math.min(...numbers); // 1

var numbers = [9, 4, 7, 1];
(_Math = Math).min.apply(_Math, numbers);


Destructuring Fun

let { x, y, ...z } = { x: 1, y: 2, a: 3, b: 4 };
console.log(x); // 1
console.log(y); // 2
console.log(z); // { a: 3, b: 4 }

var _Math;
function _objectWithoutProperties(obj, keys) {
    var target = {};
    for (var i in obj) {
        if (window.CP.shouldStopExecution(1)) {
            break;
        }
        if (keys.indexOf(i) >= 0)
            continue;
        if (!Object.prototype.hasOwnProperty.call(obj, i))
            continue;
        target[i] = obj[i];
    }
    window.CP.exitedLoop(1);
    return target;
}
var _x$y$a$b = {x: 1, y: 2, a: 3, b: 4};
var x = _x$y$a$b.x;
var y = _x$y$a$b.y;
var z = _objectWithoutProperties(_x$y$a$b, ['x', 'y']);
console.log(x);
console.log(y);
console.log(z);