Package Exports

symbol-es6

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (symbol-es6) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

Symbol-ES6

Provides support for Symbol API of ES6 in ES5 for older JS environments i.e. older browsers or NodeJS. To get full implementations of ES6 in ES5, install es6-harmony module.

Polyfills

Symbol
- for()
- keyFor
- @@hasInstance
- @@isConcatSpreadable
- @@iterator
- @@toStringTag
- Symbol.prototype.toString()
- Symbol.prototype.valueOf()
Function
- Function.prototype[@@hasInstance]()
Array
- Array.prototype.concat() (ES6 version, addition of @@isConcatSpreadable support)
- Array.prototype[@@iterator]()
- Array.from()
- Array.prototype.entries()
- Array.prototype.keys()
Object
- Object.prototype.toString() (ES6 version, addition of @@toStringTag support)
String
- String.prototype[@@iterator]()

Limitation

Some ES6 features can't be implemented in ES5 natively like spread operator, for..of loop, ES6 version of instanceOf operator etc. So this module exports a object named ES6 globally, that provides some approximate equivalent implementation of those features.

`ES6` Object

This object provides,

isSymbol() (It can be used as equivalent API of: typeof symbol === 'symbol')
instanceOf() (Provides ES6 version of instanceOf)
forOf() (This method behaves exactly same as ES6 for...of loop)
spreadOperator (Gives same functionality of the spread operator of ES6)

Examples

"use strict";

require("symbol-es6");

console.log(Symbol("bar") === Symbol("bar")); //false

var sym = Symbol.for("bar");
var sym2 = Symbol("bar");

console.log(Symbol.for("bar") === sym); //true
console.log(sym === sym2); //false
console.log(Symbol.keyFor(sym)); //bar
console.log(Symbol.keyFor(sym2)); //undefined

console.log(Array.from("Hello")); //[ 'H', 'e', 'l', 'l', 'o' ]

var it = [1, 2].entries();

console.log(it.next()); //{ done: false, value: [ 0, 1 ] }
console.log(it.next()); //{ done: false, value: [ 1, 2 ] }
console.log(it.next()); //{ done: true, value: undefined }

it = [1, 2].keys();

console.log(it.next()); //{ done: false, value: 0 }
console.log(it.next()); //{ done: false, value: 1 }
console.log(it.next()); //{ done: true, value: undefined }

function Bar() {

}
console.log(Object.prototype.toString.call(new Bar())); //[object Object]

Bar.prototype[Symbol.toStringTag] = "Bar";

console.log(Object.prototype.toString.call(new Bar())); //[object Bar]

it = "Bar"[Symbol.iterator]();

console.log(it.next()); //{ done: false, value: 'B' }
console.log(it.next()); //{ done: false, value: 'a' }
console.log(it.next()); //{ done: false, value: 'r' }


console.log(ES6.isSymbol({})); //fasle
console.log(ES6.isSymbol(sym)); ///true

function Baz() {

}
console.log(ES6.instanceOf(89, Baz)); //false
Object.defineProperty(Baz, Symbol.hasInstance, {
   value: function (value) {
       return typeof value === "number";
   }
});
console.log(ES6.instanceOf(89, Baz)); //true

ES6.forOf([1, 2], function (v) {
    console.log(v);
});
//1
//2

console.log(ES6.spreadOperator([]).spread("Bar").array()); //[ 'B', 'a', 'r' ]

function TestSpread() {
    return Array.prototype.reduce.call(arguments, function (acc, currvalue) {
        return acc + currvalue;
    }, 0);
}

console.log(ES6.spreadOperator(TestSpread).spread([1, 2, 3, 4, 5]).call()); //15

function Student(name, roll) {
    this.name = name;
    this.roll = roll;
}

console.log(ES6.spreadOperator(Student).spread(["Ariyan", 10]).new().name); //Ariyan

Installation

In browser context, just insert this script on the top of other scripts
For NodeJS, just install it from npm

npm install symbol-es6

Testing

`npm test`

Contributors

Ariyan Khan

License

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

symbol-es6