core-js
Version:
Standard library
1,258 lines (1,130 loc) • 40.4 kB
Markdown
# Core.js
Alternative modular compact (max. ~23kb w/o gzip) standard library for JavaScript. Includes polyfills for [ECMAScript 5](#ecmascript-5), [ECMAScript 6](#ecmascript-6): [symbols](#ecmascript-6-symbols), [collections](#ecmascript-6-collections), [iterators](#ecmascript-6-iterators), [promises](#ecmascript-6-promises); [setImmediate](#setimmediate), [array generics](#mozilla-javascript-array-generics), [console cap](#console). Some additional functionality such as [dictionaries](#dict), [extended partial application](#partial-application), [date formatting](#date-formatting).
[Example](http://goo.gl/mfHYm2):
```javascript
console.log(Array.from(new Set([1, 2, 3, 2, 1]))); // => [1, 2, 3]
console.log('*'.repeat(10)); // => '**********'
Promise.resolve(32).then(console.log); // => 32
setImmediate(console.log, 42); // => 42
```
[Without extension of native objects](http://goo.gl/WBhs43):
```javascript
var log = core.console.log;
log(core.Array.from(new core.Set([1, 2, 3, 2, 1]))); // => [1, 2, 3]
log(core.String.repeat('*', 10)); // => '**********'
core.Promise.resolve(32).then(log); // => 32
core.setImmediate(log, 42); // => 42
```
- [API](#api)
- [ECMAScript 5](#ecmascript-5)
- [ECMAScript 6](#ecmascript-6)
- [ECMAScript 6: Symbols](#ecmascript-6-symbols)
- [ECMAScript 6: Collections](#ecmascript-6-collections)
- [ECMAScript 6: Iterators](#ecmascript-6-iterators)
- [ECMAScript 6: Promises](#ecmascript-6-promises)
- [ECMAScript 7](#ecmascript-7)
- [ECMAScript 7: Abstract References](#ecmascript-7-abstract-references)
- [Mozilla JavaScript: Array generics](#mozilla-javascript-array-generics)
- [setTimeout / setInterval](#settimeout--setinterval)
- [setImmediate](#setimmediate)
- [console](#console)
- [Object](#object)
- [Dict](#dict)
- [Partial application](#partial-application)
- [Date formatting](#date-formatting)
- [Array](#array)
- [Number](#number)
- [Escaping characters](#escaping-characters)
- [Install](#install)
- [Changelog](#changelog)
## API:
### ECMAScript 5
Module `es5`, nothing new - without examples.
```javascript
Object
.create(proto | null, descriptors?) -> object
.getPrototypeOf(object) -> proto | null
.defineProperty(target, key, desc) -> target, cap for ie8-
.defineProperties(target, descriptors) -> target, cap for ie8-
.getOwnPropertyDescriptor(object, key) -> desc
.getOwnPropertyNames(object) -> array
.keys(object) -> array
Array
.isArray(var) -> bool
#slice(start?, end?) -> array, fix for ie7-
#join(string = ',') -> string, fix for ie7-
#indexOf(var, from?) -> int
#lastIndexOf(var, from?) -> int
#every(fn(val, index, @), that) -> bool
#some(fn(val, index, @), that) -> bool
#forEach(fn(val, index, @), that) -> void
#map(fn(val, index, @), that) -> array
#filter(fn(val, index, @), that) -> array
#reduce(fn(memo, val, index, @), memo?) -> var
#reduceRight(fn(memo, val, index, @), memo?) -> var
Function
#bind(object, ...args) -> boundFn(...args)
String
#trim() -> str
Date
.now() -> int
```
### ECMAScript 6
Module `es6`. About iterators from this module [here](#ecmascript-6-iterators). [Symbols](#ecmascript-6-symbols), [collections](#ecmascript-6-collections) and [promises](#ecmascript-6-promises) in separate modules.
#### ECMAScript 6: Object
```javascript
Object
.assign(target, ...src) -> target
.is(a, b) -> bool
.setPrototypeOf(target, proto | null) -> target, sham(ie10+)
#toString() -> string, fix for @@toStringTag support
```
[Example](http://goo.gl/VzmY3j):
```javascript
var foo = {q: 1, w: 2}
, bar = {e: 3, r: 4}
, baz = {t: 5, y: 6};
Object.assign(foo, bar, baz); // => foo = {q: 1, w: 2, e: 3, r: 4, t: 5, y: 6}
Object.is(NaN, NaN); // => true
Object.is(0, -0); // => false
Object.is(42, 42); // => true
Object.is(42, '42'); // => false
function Parent(){}
function Child(){}
Object.setPrototypeOf(Child.prototype, Parent.prototype);
new Child instanceof Child; // => true
new Child instanceof Parent; // => true
var O = {};
O[Symbol.toStringTag] = 'Foo';
'' + O; // => '[object Foo]'
```
#### ECMAScript 6: Array
```javascript
Array
.from(iterable | array-like, mapFn(val, index)?, that) -> array
.of(...args) -> array
#copyWithin(target = 0, start = 0, end = @length) -> @
#fill(var, start = 0, end = @length) -> @
#find(fn(val, index, @), that) -> var
#findIndex(fn(val, index, @), that) -> int
```
[Example](http://goo.gl/nxmJTe):
```javascript
Array.from(new Set([1, 2, 3, 2, 1])); // => [1, 2, 3]
Array.from({0: 1, 1: 2, 2: 3, length: 3}); // => [1, 2, 3]
Array.from('123', Number); // => [1, 2, 3]
Array.from('123', function(it){
return it * it;
}); // => [1, 4, 9]
Array.of(1); // => [1]
Array.of(1, 2, 3); // => [1, 2, 3]
function isOdd(val){
return val % 2;
}
[4, 8, 15, 16, 23, 42].find(isOdd); // => 15
[4, 8, 15, 16, 23, 42].findIndex(isOdd); // => 2
[4, 8, 15, 16, 23, 42].find(isNaN); // => undefined
[4, 8, 15, 16, 23, 42].findIndex(isNaN); // => -1
Array(5).fill(42); // => [42, 42, 42, 42, 42]
[1, 2, 3, 4, 5].copyWithin(0, 3); // => [4, 5, 3, 4, 5]
```
#### ECMAScript 6: String & RegExp
```javascript
String
.fromCodePoint(...codePoints) -> str
.raw({raw}, ...substitutions) -> str
#includes(str, from?) -> bool
#startsWith(str, from?) -> bool
#endsWith(str, from?) -> bool
#repeat(num) -> str
#codePointAt(pos) -> uint
RegExp
#flags -> str (getter, IE9+)
```
[Example](http://goo.gl/gbP8Io):
```javascript
'foobarbaz'.includes('bar'); // => true
'foobarbaz'.includes('bar', 4); // => false
'foobarbaz'.startsWith('foo'); // => true
'foobarbaz'.startsWith('bar', 3); // => true
'foobarbaz'.endsWith('baz'); // => true
'foobarbaz'.endsWith('bar', 6); // => true
'string'.repeat(3); // => 'stringstringstring'
'𠮷'.codePointAt(0); // => 134071
String.fromCodePoint(97, 134071, 98); // => 'a𠮷b'
var name = 'Bob';
String.raw`Hi\n${name}!`; // => 'Hi\\nBob!'
String.raw({raw: 'test'}, 0, 1, 2); // => 't0e1s2t'
/foo/.flags; // => ''
/foo/gim.flags; // => 'gim'
```
#### ECMAScript 6: Number & Math
```javascript
Number
.EPSILON -> num
.isFinite(num) -> bool
.isInteger(num) -> bool
.isNaN(num) -> bool
.isSafeInteger(num) -> bool
.MAX_SAFE_INTEGER -> int
.MIN_SAFE_INTEGER -> int
.parseFloat(str) -> num
.parseInt(str) -> int
Math
.acosh(num) -> num
.asinh(num) -> num
.atanh(num) -> num
.cbrt(num) -> num
.clz32(num) -> uint
.cosh(num) -> num
.expm1(num) -> num
.fround(num) -> num (IE10+)
.hypot(...args) -> num
.imul(num, num) -> int
.log1p(num) -> num
.log10(num) -> num
.log2(num) -> num
.sign(num) -> 1 | -1 | 0 | -0 | NaN
.sinh(num) -> num
.tanh(num) -> num
.trunc(num) -> num
```
### ECMAScript 6: Symbols
Module `es6_symbol`.
```javascript
Symbol(description?) -> symbol
.hasInstance -> @@hasInstance
.isConcatSpreadable -> @@isConcatSpreadable
.iterator -> @@iterator
.match -> @@match
.replace -> @@replace
.search -> @@search
.species -> @@species
.split -> @@split
.toPrimitive -> @@toPrimitive
.toStringTag -> @@toStringTag
.unscopables -> @@unscopables
.for(key) -> symbol
.keyFor(symbol) -> key
.useSimple() -> void
.useSetter() -> void
.pure(description?) -> symbol || string
.set(object, key, val) -> object
Reflect -> object
.ownKeys(object) -> array
```
[Basic example](http://goo.gl/BbvWFc):
```javascript
var Person = (function(){
var NAME = Symbol('name');
function Person(name){
this[NAME] = name;
}
Person.prototype.getName = function(){
return this[NAME];
};
return Person;
})();
var person = new Person('Vasya');
console.log(person.getName()); // => 'Vasya'
console.log(person['name']); // => undefined
console.log(person[Symbol('name')]); // => undefined, symbols are uniq
for(var key in person)console.log(key); // => only 'getName', symbols are not enumerable
```
`Symbol.for` & `Symbol.keyFor` [example](http://goo.gl/0pdJjX):
```javascript
var symbol = Symbol.for('key');
symbol === Symbol.for('key'); // true
Symbol.keyFor(symbol); // 'key'
```
`Reflect.ownKeys` return all object keys - strings & symbols, [example](http://goo.gl/fyu6pn):
```javascript
var O = {a: 1};
Object.defineProperty(O, 'b', {value: 2});
O[Symbol('c')] = 3;
Reflect.ownKeys(O); // => ['a', 'b', Symbol(c)]
```
By default, `Symbol` polyfill define setter in `Object.prototype`. You can disable it. [Example](http://goo.gl/N5UD7J):
```javascript
Symbol.useSimple();
var s1 = Symbol('s1')
, o1 = {};
o1[s1] = true;
for(var key in o1)log(key); // => 'Symbol(s1)_t.qamkg9f3q', w/o native Symbol
Symbol.useSetter();
var s2 = Symbol('s2')
, o2 = {};
o2[s2] = true;
for(var key in o2)log(key); // nothing
```
### ECMAScript 6: Collections
Module `es6_collections`. About iterators from this module [here](#ecmascript-6-iterators).
#### Map
```javascript
new Map(iterable (entries) ?) -> map
#clear() -> void
#delete(key) -> bool
#forEach(fn(val, key, @), that) -> void
#get(key) -> val
#has(key) -> bool
#set(key, val) -> @
#size
```
[Example](http://goo.gl/RDbROF):
```javascript
var a = [1];
var map = new Map([['a', 1], [42, 2]]);
map.set(a, 3).set(true, 4);
console.log(map.size); // => 4
console.log(map.has(a)); // => true
console.log(map.has([1])); // => false
console.log(map.get(a)); // => 3
map.forEach(function(val, key){
console.log(val); // => 1, 2, 3, 4
console.log(key); // => 'a', 42, [1], true
});
map.delete(a);
console.log(map.size); // => 3
console.log(map.get(a)); // => undefined
console.log(Array.from(map)); // => [['a', 1], [42, 2], [true, 4]]
```
#### Set
```javascript
new Set(iterable?) -> set
#add(key) -> @
#clear() -> void
#delete(key) -> bool
#forEach(fn(el, el, @), that) -> void
#has(key) -> bool
#size
```
[Example](http://goo.gl/7XYya3):
```javascript
var set = new Set(['a', 'b', 'a', 'c']);
set.add('d').add('b').add('e');
console.log(set.size); // => 5
console.log(set.has('b')); // => true
set.forEach(function(it){
console.log(it); // => 'a', 'b', 'c', 'd', 'e'
});
set.delete('b');
console.log(set.size); // => 4
console.log(set.has('b')); // => false
console.log(Array.from(set)); // => ['a', 'c', 'd', 'e']
```
#### WeakMap
```javascript
new WeakMap(iterable (entries) ?) -> weakmap
#delete(key) -> bool
#get(key) -> val
#has(key) -> bool
#set(key, val) -> @
```
[Example](http://goo.gl/SILXyw):
```javascript
var a = [1]
, b = [2]
, c = [3];
var wmap = new WeakMap([[a, 1], [b, 2]]);
wmap.set(c, 3).set(b, 4);
console.log(wmap.has(a)); // => true
console.log(wmap.has([1])); // => false
console.log(wmap.get(a)); // => 1
wmap.delete(a);
console.log(wmap.get(a)); // => undefined
// Private properties store:
var Person = (function(){
var names = new WeakMap;
function Person(name){
names.set(this, name);
}
Person.prototype.getName = function(){
return names.get(this);
};
return Person;
})();
var person = new Person('Vasya');
console.log(person.getName()); // => 'Vasya'
for(var key in person)console.log(key); // => only 'getName'
```
#### WeakSet
```javascript
new WeakSet(iterable?) -> weakset
#add(key) -> @
#delete(key) -> bool
#has(key) -> bool
```
[Example](http://goo.gl/TdFbEx):
```javascript
var a = [1]
, b = [2]
, c = [3];
var wset = new WeakSet([a, b, a]);
wset.add(c).add(b).add(c);
console.log(wset.has(b)); // => true
console.log(wset.has([2])); // => false
wset.delete(b);
console.log(wset.has(b)); // => false
```
### ECMAScript 6: Iterators
Module `es6`:
```javascript
String
#@@iterator() -> iterator
Array
#values() -> iterator
#keys() -> iterator
#entries() -> iterator (entries)
#@@iterator() -> iterator
Arguments
#@@iterator() -> iterator (sham, available only in core-js methods)
```
Module `es6_collections`:
```javascript
Set
#values() -> iterator
#keys() -> iterator
#entries() -> iterator (entries)
#@@iterator() -> iterator
Map
#values() -> iterator
#keys() -> iterator
#entries() -> iterator (entries)
#@@iterator() -> iterator (entries)
```
[Example](http://goo.gl/3s27dC):
```javascript
var string = 'a𠮷b';
for(var val of string)console.log(val); // => 'a', '𠮷', 'b'
var array = ['a', 'b', 'c'];
for(var val of array)console.log(val); // => 'a', 'b', 'c'
for(var val of array.values())console.log(val); // => 'a', 'b', 'c'
for(var key of array.keys())console.log(key); // => 0, 1, 2
for(var [key, val] of array.entries()){
console.log(key); // => 0, 1, 2
console.log(val); // => 'a', 'b', 'c'
}
var map = new Map([['a', 1], ['b', 2], ['c', 3]]);
for(var [key, val] of map){
console.log(key); // => 'a', 'b', 'c'
console.log(val); // => 1, 2, 3
}
for(var val of map.values())console.log(val); // => 1, 2, 3
for(var key of map.keys())console.log(key); // => 'a', 'b', 'c'
for(var [key, val] of map.entries()){
console.log(key); // => 'a', 'b', 'c'
console.log(val); // => 1, 2, 3
}
var set = new Set([1, 2, 3, 2, 1]);
for(var val of set)console.log(val); // => 1, 2, 3
for(var val of set.values())console.log(val); // => 1, 2, 3
for(var key of set.keys())console.log(key); // => 1, 2, 3
for(var [key, val] of set.entries()){
console.log(key); // => 1, 2, 3
console.log(val); // => 1, 2, 3
}
```
Module `$for` - iterators chaining - `for-of` and array / generator comprehensions helpers for ES5- syntax.
```javascript
$for(iterable, entries) -> iterator ($for)
#of(fn(value, key?), that) -> void
#array(mapFn(value, key?)?, that) -> array
#filter(fn(value, key?), that) -> iterator ($for)
#map(fn(value, key?), that) -> iterator ($for)
.isIterable(var) -> bool
.getIterator(iterable) -> iterator
```
[Examples](http://goo.gl/Jtz0oG):
```javascript
$for(new Set([1, 2, 3, 2, 1])).of(function(it){
console.log(it); // => 1, 2, 3
});
$for([1, 2, 3].entries(), true).of(function(key, value){
console.log(key); // => 0, 1, 2
console.log(value); // => 1, 2, 3
});
$for('abc').of(console.log, console); // => 'a', 'b', 'c'
$for([1, 2, 3, 4, 5]).of(function(it){
console.log(it); // => 1, 2, 3
if(it == 3)return false;
});
var ar1 = $for([1, 2, 3]).array(function(v){
return v * v;
}); // => [1, 4, 9]
var set = new Set([1, 2, 3, 2, 1]);
var ar1 = $for(set).filter(function(v){
return v % 2;
}).array(function(v){
return v * v;
}); // => [1, 9]
var iter = $for(set).filter(function(v){
return v % 2;
}).map(function(v){
return v * v;
});
iter.next(); // => {value: 1, done: false}
iter.next(); // => {value: 9, done: false}
iter.next(); // => {value: undefined, done: true}
var map1 = new Map([['a', 1], ['b', 2], ['c', 3]]);
var map2 = new Map($for(map1, true).filter(function(k, v){
return v % 2;
}).map(function(k, v){
return [k + k, v * v];
})); // => Map {aa: 1, cc: 9}
```
### ECMAScript 6: Promises
Module `es6_promise`.
```javascript
new Promise(executor(resolve(var), reject(var))) -> promise
#then(resolved(var), rejected(var)) -> promise
#catch(rejected(var)) -> promise
.resolve(var || promise) -> promise
.reject(var) -> promise
.all(iterable) -> promise
.race(iterable) -> promise
```
Basic [example](http://goo.gl/vGrtUC):
```javascript
var log = console.log.bind(console);
function sleepRandom(time){
return new Promise(function(resolve, reject){
setTimeout(resolve, time * 1e3, 0 | Math.random() * 1e3);
});
}
log('Run'); // => Run
sleepRandom(5).then(function(result){
log(result); // => 869, after 5 sec.
return sleepRandom(10);
}).then(function(result){
log(result); // => 202, after 10 sec.
}).then(function(){
log('immediately after'); // => immediately after
throw Error('Irror!');
}).then(function(){
log('will not be displayed');
}).catch(log); // => => Error: Irror!
```
`Promise.resolve` and `Promise.reject` [example](http://goo.gl/vr8TN3):
```javascript
Promise.resolve(42).then(log); // => 42
Promise.reject(42).catch(log); // => 42
Promise.resolve($.getJSON('/data.json')); // => ES6 promise
```
`Promise.all` [example](http://goo.gl/RdoDBZ):
```javascript
Promise.all([
'foo',
sleepRandom(5),
sleepRandom(15),
sleepRandom(10) // after 15 sec:
]).then(log); // => ['foo', 956, 85, 382]
```
`Promise.race` [example](http://goo.gl/L8ovkJ):
```javascript
function timeLimit(promise, time){
return Promise.race([promise, new Promise(function(resolve, reject){
setTimeout(reject, time * 1e3, Error('Await > ' + time + ' sec'));
})]);
}
timeLimit(sleepRandom(5), 10).then(log); // => 853, after 5 sec.
timeLimit(sleepRandom(15), 10).catch(log); // Error: Await > 10 sec
```
ECMAScript 7 [async functions](https://github.com/lukehoban/ecmascript-asyncawait) [example](http://goo.gl/rksdJx):
```javascript
var delay = time => new Promise(resolve => setTimeout(resolve, time))
async function sleepRandom(time){
await delay(time * 1e3);
return 0 | Math.random() * 1e3;
}
async function sleepError(time, msg){
await delay(time * 1e3);
throw Error(msg);
}
(async () => {
try {
log('Run'); // => Run
log(await sleepRandom(5)); // => 936, after 5 sec.
var [a, b, c] = await Promise.all([
sleepRandom(5),
sleepRandom(15),
sleepRandom(10)
]);
log(a, b, c); // => 210 445 71, after 15 sec.
await sleepError(5, 'Irror!');
log('Will not be displayed');
} catch(e){
log(e); // => Error: 'Irror!', after 5 sec.
}
})();
```
### ECMAScript 7
Module `es7`.
* `Array#includes` [proposal](https://github.com/domenic/Array.prototype.includes)
* `String#at` [proposal](https://github.com/mathiasbynens/String.prototype.at)
* `Object.values`, `Object.entries` [tc39 discuss](https://github.com/rwaldron/tc39-notes/blob/master/es6/2014-04/apr-9.md#51-objectentries-objectvalues)
* `RegExp.escape` [proposal](https://gist.github.com/kangax/9698100)
```javascript
Array
#includes(var, from?) -> bool
String
#at(index) -> string
Object
.values(object) -> array
.entries(object) -> array
RegExp
.escape(str) -> str
```
[Examples](http://goo.gl/4HcpLK):
```javascript
[1, 2, 3].includes(2); // => true
[1, 2, 3].includes(4); // => false
[1, 2, 3].includes(2, 2); // => false
[NaN].indexOf(NaN); // => -1
[NaN].includes(NaN); // => true
Array(1).indexOf(undefined); // => -1
Array(1).includes(undefined); // => true
'a𠮷b'.at(1); // => '𠮷'
'a𠮷b'.at(1).length; // => 2
Object.values({a: 1, b: 2, c: 3}); // => [1, 2, 3]
Object.entries({a: 1, b: 2, c: 3}); // => [['a', 1], ['b', 2], ['c', 3]]
RegExp.escape('Hello -[]{}()*+?.,\\^$|'); // => 'Hello \-\[\]\{\}\(\)\*\+\?\.\,\\\^\$\|'
```
### ECMAScript 7: Abstract References
Module `es7_refs`. Symbols and methods for [abstract references](https://github.com/zenparsing/es-abstract-refs). At the moment, they are supported only by several translators, such as [6to5](https://github.com/6to5/6to5).
```javascript
Symbol
.referenceGet -> @@referenceGet
.referenceSet -> @@referenceSet
.referenceDelete -> @@referenceDelete
Function
#@@referenceGet() -> @
Map
#@@referenceGet ==== #get
#@@referenceSet ==== #set
#@@referenceDelete ==== #delete
WeakMap
#@@referenceGet ==== #get
#@@referenceSet ==== #set
#@@referenceDelete ==== #delete
```
Private properties [example](http://goo.gl/sO0KHa) with [`WeakMaps`](#weakmap), class and basic abstract refs syntax:
```javascript
var Person = (NAME => class {
constructor(name){
this::NAME = name;
}
getName(){
return this::NAME;
}
})(new WeakMap);
var person = new Person('Vasya');
console.log(person.getName()); // => 'Vasya'
for(var key in person)console.log(key); // => only 'getName'
```
Virtual methods [example](http://goo.gl/GJmEfl):
```javascript
var {toString} = {};
console.log([]::toString()); // => '[object Array]'
function sum(){
var {reduce} = [];
return arguments::reduce((a, b)=> a + b);
}
console.log(sum(1, 2, 3, 4, 5)); // => 15
```
Methods from [Dict module](#dict) override `@@referenceGet` method, [example](http://goo.gl/vgIKJ2):
```javascript
var {filter, map} = Dict;
var dict = {q: 1, w: 2, e: 3}::filter((v, k) => k != 'w')::map(v => v * v); // => {"q":1,"e":9}
```
### Mozilla JavaScript: Array generics
Module `array_statics`.
```javascript
Array
.{...ArrayPrototype methods}
```
```javascript
Array.slice(arguments, 1);
Array.join('abcdef', '+'); // => 'a+b+c+d+e+f'
var form = document.getElementsByClassName('form__input');
Array.reduce(form, function(memo, it){
memo[it.name] = it.value;
return memo;
}, {}); // => {name: 'Vasya', age: '42', sex: 'yes, please'}
```
### setTimeout / setInterval
Module `timers`. Additional arguments fix for IE9-.
```javascript
setTimeout(fn(...args), time, ...args) -> id
setInterval(fn(...args), time, ...args) -> id
```
```javascript
// Before:
setTimeout(log.bind(null, 42), 1000);
// After:
setTimeout(log, 1000, 42);
```
### setImmediate
Module `immediate`. [setImmediate](https://developer.mozilla.org/en-US/docs/Web/API/Window.setImmediate) polyfill.
```javascript
setImmediate(fn(...args), ...args) -> id
clearImmediate(id) -> void
```
### Console
Module `console`. Console cap for old browsers and some additional functionality.
```javascript
console
.{...console API}
.enable() -> void
.disable() -> void
```
```javascript
// Before:
if(window.console && console.log)console.log(42);
// After:
console.log(42);
// Before:
setTimeout(console.log.bind(console, 42), 1000);
[1, 2, 3].forEach(console.log, console);
// After:
setTimeout(console.log, 1000, 42);
[1, 2, 3].forEach(console.log);
console.disable();
console.warn('Console is disabled, you will not see this message.');
console.enable();
console.warn('Console is enabled again.');
```
### Object
Module `object`.
```javascript
Object
.isObject(var) -> bool
.classof(var) -> string
.define(target, mixin) -> target
.make(proto | null, mixin?) -> object
```
Object classify [examples](http://goo.gl/YZQmGo):
```javascript
Object.isObject({}); // => true
Object.isObject(isNaN); // => true
Object.isObject(null); // => false
var classof = Object.classof;
classof(null); // => 'Null'
classof(undefined); // => 'Undefined'
classof(1); // => 'Number'
classof(true); // => 'Boolean'
classof('string'); // => 'String'
classof(Symbol()); // => 'Symbol'
classof(new Number(1)); // => 'Number'
classof(new Boolean(true)); // => 'Boolean'
classof(new String('string')); // => 'String'
var fn = function(){}
, list = (function(){return arguments})(1, 2, 3);
classof({}); // => 'Object'
classof(fn); // => 'Function'
classof([]); // => 'Array'
classof(list); // => 'Arguments'
classof(/./); // => 'RegExp'
classof(new TypeError); // => 'Error'
classof(new Set); // => 'Set'
classof(new Map); // => 'Map'
classof(new WeakSet); // => 'WeakSet'
classof(new WeakMap); // => 'WeakMap'
classof(new Promise(fn)); // => 'Promise'
classof([].values()); // => 'Array Iterator'
classof(new Set().values()); // => 'Set Iterator'
classof(new Map().values()); // => 'Map Iterator'
classof(Math); // => 'Math'
classof(JSON); // => 'JSON'
function Example(){}
Example.prototype[Symbol.toStringTag] = 'Example';
classof(new Example); // => 'Example'
```
`Object.define` and `Object.make` [examples](http://goo.gl/rtpD5Z):
```javascript
// Before:
Object.defineProperty(target, 'c', {
enumerable: true,
configurable: true,
get: function(){
return this.a + this.b;
}
});
// After:
Object.define(target, {
get c(){
return this.a + this.b;
}
});
// Shallow object cloning with prototype and descriptors:
var copy = Object.make(Object.getPrototypeOf(src), src);
// Simple inheritance:
function Vector2D(x, y){
this.x = x;
this.y = y;
}
Object.define(Vector2D.prototype, {
get xy(){
return Math.hypot(this.x, this.y);
}
});
function Vector3D(x, y, z){
Vector2D.apply(this, arguments);
this.z = z;
}
Vector3D.prototype = Object.make(Vector2D.prototype, {
constructor: Vector3D,
get xyz(){
return Math.hypot(this.x, this.y, this.z);
}
});
var vector = new Vector3D(9, 12, 20);
console.log(vector.xy); // => 15
console.log(vector.xyz); // => 25
vector.y++;
console.log(vector.xy); // => 15.811388300841896
console.log(vector.xyz); // => 25.495097567963924
```
### Dict
Module `dict`. Based on [TC39 discuss](https://github.com/rwaldron/tc39-notes/blob/master/es6/2012-11/nov-29.md#collection-apis-review) / [strawman](http://wiki.ecmascript.org/doku.php?id=harmony:modules_standard#dictionaries).
```javascript
[new] Dict(itarable (entries) | object ?) -> dict
.isDict(var) -> bool
.values(object) -> iterator
.keys(object) -> iterator
.entries(object) -> iterator (entries)
.has(object, key) -> bool
.get(object, key) -> val
.set(object, key, value) -> object
.forEach(object, fn(val, key, @), that) -> void
.map(object, fn(val, key, @), that) -> new @
.mapPairs(object, fn(val, key, @), that) -> new @
.filter(object, fn(val, key, @), that) -> new @
.some(object, fn(val, key, @), that) -> bool
.every(object, fn(val, key, @), that) -> bool
.find(object, fn(val, key, @), that) -> val
.findKey(object, fn(val, key, @), that) -> key
.keyOf(object, var) -> key
.includes(object, var) -> bool
.reduce(object, fn(memo, val, key, @), memo?) -> var
.turn(object, fn(memo, val, key, @), memo = new @) -> memo
```
`Dict` create object without prototype from iterable or simple object. [Example](http://goo.gl/pnp8Vr):
```javascript
var map = new Map([['a', 1], ['b', 2], ['c', 3]]);
Dict(); // => {__proto__: null}
Dict({a: 1, b: 2, c: 3}); // => {__proto__: null, a: 1, b: 2, c: 3}
Dict(map); // => {__proto__: null, a: 1, b: 2, c: 3}
Dict([1, 2, 3].entries()); // => {__proto__: null, 0: 1, 1: 2, 2: 3}
var dict = Dict({a: 42});
dict instanceof Object; // => false
dict.a; // => 42
dict.toString; // => undefined
'a' in dict; // => true
'hasOwnProperty' in dict; // => false
Dict.isDict({}); // => false
Dict.isDict(Dict()); // => true
```
`Dict.keys`, `Dict.values` and `Dict.entries` return iterators for objects, [examples](http://goo.gl/JRkgM8):
```javascript
var dict = {a: 1, b: 2, c: 3};
for(var key of Dict.keys(dict))console.log(key); // => 'a', 'b', 'c'
for(var [key, val] of Dict.entries(dict)){
console.log(key); // => 'a', 'b', 'c'
console.log(val); // => 1, 2, 3
}
$for(Dict.values(dict)).of(console.log); // => 1, 2, 3
new Map(Dict.entries(dict)); // => Map {a: 1, b: 2, c: 3}
new Map((for([k, v] of Dict.entries(dict))if(v % 2)[k + k, v * v])); // => Map {aa: 1, cc: 9}
```
Other methods of `Dict` module are static equialents of `Array.prototype` methods for dictionaries, [examples](http://goo.gl/yARYXR):
```javascript
var dict = {a: 1, b: 2, c: 3};
Dict.forEach(dict, console.log, console);
// => 1, 'a', {a: 1, b: 2, c: 3}
// => 2, 'b', {a: 1, b: 2, c: 3}
// => 3, 'c', {a: 1, b: 2, c: 3}
Dict.map(dict, function(it){
return it * it;
}); // => {a: 1, b: 4, c: 9}
Dict.mapPairs(dict, function(val, key){
if(key != 'b')return [key + key, val * val];
}); // => {aa: 1, cc: 9}
Dict.filter(dict, function(it){
return it % 2;
}); // => {a: 1, c: 3}
Dict.some(dict, function(it){
return it === 2;
}); // => true
Dict.every(dict, function(it){
return it === 2;
}); // => false
Dict.find(dict, function(it){
return it > 2;
}); // => 3
Dict.find(dict, function(it){
return it > 4;
}); // => undefined
Dict.findKey(dict, function(it){
return it > 2;
}); // => 'c'
Dict.findKey(dict, function(it){
return it > 4;
}); // => undefined
Dict.keyOf(dict, 2); // => 'b'
Dict.keyOf(dict, 4); // => undefined
Dict.includes(dict, 2); // => true
Dict.includes(dict, 4); // => false
Dict.reduce(dict, function(memo, it){
return memo + it;
}); // => 6
Dict.reduce(dict, function(memo, it){
return memo + it;
}, ''); // => '123'
Dict.turn(dict, function(memo, it, key){
memo[key + key] = it;
}); // => {aa: 1, bb: 2, cc: 3}
Dict.turn(dict, function(memo, it, key){
it % 2 && memo.push(key + it);
}, []); // => ['a1', 'c3']
```
### Partial application
Module `binding`.
```javascript
Function
#part(...args | _) -> fn(...args)
#by(object | _, ...args | _) -> boundFn(...args)
#only(num, that /* = @ */) -> (fn | boundFn)(...args)
Object
#[_](key) -> boundFn
```
`Function#part` partial apply function without `this` binding. Uses global variable `_` (`core._` for builds without extension of native objects) as placeholder. [Examples](http://goo.gl/p9ZJ8K):
```javascript
var fn1 = console.log.part(1, 2);
fn1(3, 4); // => 1, 2, 3, 4
var fn2 = console.log.part(_, 2, _, 4);
fn2(1, 3); // => 1, 2, 3, 4
var fn3 = console.log.part(1, _, _, 4);
fn3(2, 3); // => 1, 2, 3, 4
fn2(1, 3, 5); // => 1, 2, 3, 4, 5
fn2(1); // => 1, 2, undefined, 4
```
Method `Function#by` is analogue of `Function#bind` with the ability to use placeholder:
```javascript
var fn = console.log.by(console, _, 2, _, 4);
fn(1, 3, 5); // => 1, 2, 3, 4, 5
```
Method `Object#[_]` extracts bound method from object, [examples](http://goo.gl/dQsSTi):
```javascript
['foobar', 'foobaz', 'barbaz'].filter(/bar/[_]('test')); // => ['foobar', 'barbaz']
var has = {}.hasOwnProperty[_]('call');
log(has({key: 42}, 'foo')); // => false
log(has({key: 42}, 'key')); // => true
var array = []
, push = array[_]('push');
push(1);
push(2, 3);
log(array); // => [1, 2, 3];
```
Method `Function#only` limits number of arguments. [Example](http://goo.gl/ROgBsL):
```javascript
[1, 2, 3].forEach(log.only(1)); // => 1, 2, 3
```
### Date formatting
Module `date`. Much more simple and compact (~60 lines with `en` & `ru` locales) than [Intl](https://github.com/andyearnshaw/Intl.js) or [Moment.js](http://momentjs.com/). Use them if you need extended work with `Date`.
```javascript
Date
#format(str, key?) -> str
#formatUTC(str, key?) -> str
core
.addLocale(key, object) -> core
.locale(key?) -> key
```
Token | Unit | Sample
------|----- | ------
s | Seconds | 0-59
ss | Seconds, 2 digits | 00-59
m | Minutes | 0-59
mm | Minutes, 2 digits | 00-59
h | Hours | 0-23
hh | Hours, 2 digits | 00-23
D | Date | 1-31
DD | Date, 2 digits | 01-31
W | Weekday, string | Вторник
N | Month | 1-12
NN | Month, 2 digits | 01-12
M | Month, string | Ноябрь
MM | Of month, string | Ноября
Y | Year, full | 2014
YY | Year, 2 digits | 14
[Examples](http://goo.gl/nkCJ15):
```javascript
new Date().format('W, MM D, YY, h:mm:ss'); // => 'Friday, November 28, 14, 18:47:05'
new Date().formatUTC('W, MM D, YY, h:mm:ss'); // => 'Friday, November 28, 14, 12:47:05'
new Date().format('W, D MM Y г., h:mm:ss', 'ru'); // => 'Пятница, 28 Ноября 2014 г., 18:07:25'
core.locale('ru');
new Date().format('W, D MM Y г., h:mm:ss'); // => 'Пятница, 28 Ноября 2014 г., 18:07:25'
new Date().format('DD.NN.YY'); // => '28.11.14'
new Date().format('hh:mm:ss'); // => '18:47:05'
new Date().format('DD.NN.Y hh:mm:ss'); // => '28.11.2014 18:47:05'
new Date().format('W, D MM Y года'); // => 'Пятница, 28 Ноября 2014 года'
new Date().format('D MM, h:mm'); // => '28 Ноября, 16:47'
new Date().format('M Y'); // => 'Ноябрь 2014'
(typeof core != 'undefined' ? core : require('core-js/library')).addLocale('ru', {
weekdays: 'Воскресенье,Понедельник,Вторник,Среда,Четверг,Пятница,Суббота',
months: 'Январ:я|ь,Феврал:я|ь,Март:а|,Апрел:я|ь,Ма:я|й,Июн:я|ь,Июл:я|ь,Август:а|,Сентябр:я|ь,Октябр:я|ь,Ноябр:я|ь,Декабр:я|ь'
});
```
### Array
Module `array`.
```javascript
Array
#turn(fn(memo, val, index, @), memo = []) -> memo
```
Method `Array#turn` reduce array to object, [example](http://goo.gl/zZbvq7):
```javascript
[1, 2, 3, 4, 5].turn(function(memo, it){
memo['key' + it] = !!(it % 2);
}, {}); // => {key1: true, key2: false, key3: true, key4: false, key5: true}
[1, 2, 3, 4, 5, 6, 7, 8, 9].turn(function(memo, it){
it % 2 && memo.push(it * it);
if(memo.length == 3)return false;
}); // => [1, 9, 25]
```
### Number
Module `number`.
```javascript
Number
#@@iterator() -> iterator
#random(lim = 0) -> num
#{...Math}
```
Number Iterator [examples](http://goo.gl/mkReUE):
```javascript
for(var i of 3)console.log(i); // => 0, 1, 2
$for(3).of(console.log); // => 0, 1, 2
Array.from(10, Math.random); // => [0.9817775336559862, 0.02720663254149258, ...]
Array.from(10); // => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
Array.from(10, function(it){
return this + it * it;
}, .42); // => [0.42, 1.42, 4.42, 9.42, 16.42, 25.42, 36.42, 49.42, 64.42, 81.42]
// Comprehensions:
[for(i of 10)if(i % 2)i * i]; // => [1, 9, 25, 49, 81]
Dict((for(i of 3)['key' + i, !(i % 2)])); // => {key0: true, key1: false, key2: true}
$for(10).filter(function(i){
return i % 2;
}).array(function(i){
return i * i;
}); // => [1, 9, 25, 49, 81]
Dict($for(3).map(function(i){
return ['key' + i, !(i % 2)];
})); // => {key0: true, key1: false, key2: true}
```
`Math` methods in `Number.prototype` [examples](http://goo.gl/06bs1k):
```javascript
3..pow(3); // => 27
(-729).abs().sqrt(); // => 27
10..random(20); // => Random number (10, 20), for example, 16.818793776910752
10..random(20).floor(); // => Random integer [10, 19], for example, 16
var array = [1, 2, 3, 4, 5];
array[array.length.random().floor()]; // => Random element, for example, 4
```
### Escaping characters
Module `string`.
```javascript
String
#escapeHTML() -> str
#unescapeHTML() -> str
```
[Examples](http://goo.gl/6bOvsQ):
```javascript
'<script>doSomething();</script>'.escapeHTML(); // => '<script>doSomething();</script>'
'<script>doSomething();</script>'.unescapeHTML(); // => '<script>doSomething();</script>'
```
## Install
```
// Node.js:
npm i core-js
// Bower:
bower install core.js
```
Browser builds: [default](https://github.com/zloirock/core-js/raw/master/client/core.min.js), [without extension of native objects](https://github.com/zloirock/core-js/raw/master/client/core.min.js), [shim only](https://github.com/zloirock/core-js/raw/master/client/shim.min.js).
Custom builds:
```
npm i -g grunt-cli
npm i core-js
cd node_modules/core-js && npm i
grunt build:date,console,library --path=custom uglify
```
Where `date` and `console` are module names, `library` is flag for not extension of native objects and `custom` is target file name.
Require in Node.js:
```javascript
// Dafault
require('core-js');
// Without extension of native objects
var core = require('core-js/library');
// Shim only
require('core-js/shim');
```
## Changelog
**0.3.1** - *2014.12.23* - Some fixes
**0.3.0** - *2014.12.23* - Optimize [`Map` & `Set`](#ecmascript-6-collections)
* use entries chain on hash table
* fast & correct iteration
* iterators moved to [`es6`](#ecmascript-6) and [`es6_collections`](#ecmascript-6-collections) modules
**0.2.5** - *2014.12.20*
* `console` no longer shortcut for `console.log` (compatibility problems)
* some fixes
**0.2.4** - *2014.12.17* - Better compliance of ES6
* some fixes
* added [`Math.fround`](#ecmascript-6-number--math) (IE10+)
**0.2.3** - *2014.12.15* - [Symbols](#ecmascript-6-symbols):
* added option to disable addition setter to `Object.prototype` for Symbol polyfill:
* added `Symbol.useSimple`
* added `Symbol.useSetter`
* added cap for well-known Symbols:
* added `Symbol.hasInstance`
* added `Symbol.isConcatSpreadable`
* added `Symbol.match`
* added `Symbol.replace`
* added `Symbol.search`
* added `Symbol.species`
* added `Symbol.split`
* added `Symbol.toPrimitive`
* added `Symbol.unscopables`
**0.2.2** - *2014.12.13* - ES6:
* added [`RegExp#flags`](#ecmascript-6-string--regexp) ([December 2014 Draft Rev 29](http://wiki.ecmascript.org/doku.php?id=harmony:specification_drafts#december_6_2014_draft_rev_29))
* added [`String.raw`](#ecmascript-6-string--regexp)
**0.2.1** - *2014.12.12* - Repair converting -0 to +0 in [native collections](#ecmascript-6-collections)
**0.2.0** - *2014.12.06*
* added [`es7`](#ecmascript-7), [`es7_refs`](#ecmascript-7-abstract-references) modules
* added [`String#at`](#ecmascript-7)
* added real [String Iterator](#ecmascript-6-iterators), older versions used Array Iterator
* added [abstract references](#ecmascript-7-abstract-references) support:
* added `Symbol.referenceGet`
* added `Symbol.referenceSet`
* added `Symbol.referenceDelete`
* added `Function#@@referenceGet`
* added `Map#@@referenceGet`
* added `Map#@@referenceSet`
* added `Map#@@referenceDelete`
* added `WeakMap#@@referenceGet`
* added `WeakMap#@@referenceSet`
* added `WeakMap#@@referenceDelete`
* added `Dict.{...methods}[@@referenceGet]`
* removed deprecated `.contains` methods
* some fixes
**0.1.5** - *2014.12.01* - ES6:
* added [`Array#copyWithin`](#ecmascript-6-array)
* added [`String#codePointAt`](#ecmascript-6-string--regexp)
* added [`String.fromCodePoint`](#ecmascript-6-string--regexp)
**0.1.4** - *2014.11.27*
* added [`Dict.mapPairs`](#dict)
**0.1.3** - *2014.11.20* - [TC39 November meeting](https://github.com/rwaldron/tc39-notes/tree/master/es6/2014-11):
* [`.contains` -> `.includes`](https://github.com/rwaldron/tc39-notes/blob/master/es6/2014-11/nov-18.md#51--44-arrayprototypecontains-and-stringprototypecontains)
* `String#contains` -> [`String#includes`](#ecmascript-6-string--regexp)
* `Array#contains` -> [`Array#includes`](#ecmascript-7)
* `Dict.contains` -> [`Dict.includes`](#dict)
* [removed `WeakMap#clear`](https://github.com/rwaldron/tc39-notes/blob/master/es6/2014-11/nov-19.md#412-should-weakmapweakset-have-a-clear-method-markm)
* [removed `WeakSet#clear`](https://github.com/rwaldron/tc39-notes/blob/master/es6/2014-11/nov-19.md#412-should-weakmapweakset-have-a-clear-method-markm)
**0.1.2** - *2014.11.19* - Map & Set bug fix
**0.1.1** - *2014.11.18* - Public release