ecmascript-5

How do I splat across objects without using ECMA6 features ? Attempt function can(arg0, arg1) { return arg0 + arg1; } function foo(bar, haz) { this.bar = bar; this.haz = haz; } myArgs = [1,2]; With can I can just do: can.apply(this, myArgs); When trying with foo : new foo.apply(this, myArgs); I get this error (because I'm calling new ): TypeError: function apply() { [native code] } is not a constructor Using Object.create function foo(bar, haz) { this.bar = bar; this.haz = haz; } x = Object.create(foo.prototype); myArgs = [5,6]; foo.apply(x, myArgs); console.log(x.bar); Ven Using Object.create

this works as expected [97,98].map(function(x){String.fromCharCode(x)}) // [ 'a', 'b' ] but the output is following line is unexpected [97,98].map(String.fromCharCode) // [ 'a\u0000\u0000', 'b\u0001\u0000' ] String.fromCharCode can accept a variable length of arguments, and treats each one as a character code to build a string arguments.length characters long. map passes several arguments to the inner function. The first, obviously, is the value of the current item. The second is the index in the array, which is where the \u0000 and \u0001 come from (add more character codes and you get \u0002

I would like to have a computed property name. I saw you can have this in ES6. But it should be compatible with IOS Webview. So I can't use ES6. Also the computed name will be ever the same inside the loop, if this makes it easier for somebody. Any Ideas? var today = moment().format('DD.MM.YY'); for (var i = 0; i < 5; i++) { initialData.push( { dates: { "01.01.01": false // instead of 01.01.01 i would like to have the value of today as the key } } ) } You have to do it the elaborate way in ES5: var today = moment().format('DD.MM.YY'); var obj = {}; obj[today] = false; for (var i = 0; i < 5; i+

I'm trying to use defineProperty to made attributes not appear in for...in cycle, but it doesn't work. Is this code correct? function Item() { this.enumerable = "enum"; this.nonEnum = "noEnum"; } Object.defineProperty(Item, "nonEnum", { enumerable: false }); var test = new Item(); for (var tmp in test){ console.log(tmp); } Item does not have a property named nonEnum ( check it out ). It is a (constructor) function that will create an object that has a property called nonEnum . So this one would work: var test = new Item(); Object.defineProperty(test, "nonEnum", { enumerable: false }); You

we can do the following to convert: var a = "129.13"|0, // becomes 129 var b = 11.12|0; // becomes 11 var c = "112"|0; // becomes 112 This seem to work but not sure if this is a standard JS feature. Does any one have any idea if this is safe to use for converting strings and decimals to integers ? Yes, it is standard behavior. Bitwise operators only operate on integers, so they convert whatever number they're give to signed 32 bit integer. This means that the max range is that of signed 32 bit integer minus 1, which is 2147483647 . (Math.pow(2, 32) / 2 - 1)|0; // 2147483647 (Math.pow(2, 32) /

I have the following code inside my revealing module, but I am uncertain with how to declare/define imageListItem , which is strictly a DTO and doesn't really require any information hiding. Am I correctly defining this object? var imageListItem = function() { var _title; Object.defineProperty(this, "title", { get: function () { return _title; }, set: function (value) { _title = value; } } ); }; var imageList = (function () { var buffer = new CBuffer(); return { populate: function (listItems) { buffer.push(listItems); }, rotate: function() { buffer.rotateLeft(); } } })(); With imageListItem ,