149 lines
4.2 KiB
Markdown
149 lines
4.2 KiB
Markdown
# es6-iterator
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## ECMAScript 6 Iterator interface
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### Installation
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$ npm install es6-iterator
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To port it to Browser or any other (non CJS) environment, use your favorite CJS bundler. No favorite yet? Try: [Browserify](http://browserify.org/), [Webmake](https://github.com/medikoo/modules-webmake) or [Webpack](http://webpack.github.io/)
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## API
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### Constructors
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#### Iterator(list) _(es6-iterator)_
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Abstract Iterator interface. Meant for extensions and not to be used on its own.
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Accepts any _list_ object (technically object with numeric _length_ property).
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_Mind it doesn't iterate strings properly, for that use dedicated [StringIterator](#string-iterator)_
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```javascript
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var Iterator = require('es6-iterator')
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var iterator = new Iterator([1, 2, 3]);
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iterator.next(); // { value: 1, done: false }
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iterator.next(); // { value: 2, done: false }
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iterator.next(); // { value: 3, done: false }
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iterator.next(); // { value: undefined, done: true }
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```
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#### ArrayIterator(arrayLike[, kind]) _(es6-iterator/array)_
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Dedicated for arrays and array-likes. Supports three iteration kinds:
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* __value__ _(default)_ - Iterates values
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* __key__ - Iterates indexes
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* __key+value__ - Iterates keys and indexes, each iteration value is in _[key, value]_ form.
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```javascript
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var ArrayIterator = require('es6-iterator/array')
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var iterator = new ArrayIterator([1, 2, 3], 'key+value');
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iterator.next(); // { value: [0, 1], done: false }
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iterator.next(); // { value: [1, 2], done: false }
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iterator.next(); // { value: [2, 3], done: false }
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iterator.next(); // { value: undefined, done: true }
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```
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May also be used for _arguments_ objects:
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```javascript
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(function () {
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var iterator = new ArrayIterator(arguments);
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iterator.next(); // { value: 1, done: false }
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iterator.next(); // { value: 2, done: false }
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iterator.next(); // { value: 3, done: false }
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iterator.next(); // { value: undefined, done: true }
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}(1, 2, 3));
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```
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#### StringIterator(str) _(es6-iterator/string)_
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Assures proper iteration over unicode symbols.
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See: http://mathiasbynens.be/notes/javascript-unicode
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```javascript
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var StringIterator = require('es6-iterator/string');
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var iterator = new StringIterator('f🙈o🙉o🙊');
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iterator.next(); // { value: 'f', done: false }
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iterator.next(); // { value: '🙈', done: false }
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iterator.next(); // { value: 'o', done: false }
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iterator.next(); // { value: '🙉', done: false }
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iterator.next(); // { value: 'o', done: false }
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iterator.next(); // { value: '🙊', done: false }
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iterator.next(); // { value: undefined, done: true }
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```
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### Function utilities
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#### forOf(iterable, callback[, thisArg]) _(es6-iterator/for-of)_
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Polyfill for ECMAScript 6 [`for...of`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...of) statement.
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```
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var forOf = require('es6-iterator/for-of');
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var result = [];
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forOf('🙈🙉🙊', function (monkey) { result.push(monkey); });
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console.log(result); // ['🙈', '🙉', '🙊'];
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```
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Optionally you can break iteration at any point:
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```javascript
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var result = [];
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forOf([1,2,3,4]', function (val, doBreak) {
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result.push(monkey);
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if (val >= 3) doBreak();
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});
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console.log(result); // [1, 2, 3];
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```
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#### get(obj) _(es6-iterator/get)_
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Return iterator for any iterable object.
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```javascript
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var getIterator = require('es6-iterator/get');
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var iterator = get([1,2,3]);
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iterator.next(); // { value: 1, done: false }
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iterator.next(); // { value: 2, done: false }
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iterator.next(); // { value: 3, done: false }
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iterator.next(); // { value: undefined, done: true }
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```
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#### isIterable(obj) _(es6-iterator/is-iterable)_
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Whether _obj_ is iterable
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```javascript
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var isIterable = require('es6-iterator/is-iterable');
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isIterable(null); // false
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isIterable(true); // false
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isIterable('str'); // true
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isIterable(['a', 'r', 'r']); // true
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isIterable(new ArrayIterator([])); // true
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```
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#### validIterable(obj) _(es6-iterator/valid-iterable)_
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If _obj_ is an iterable it is returned. Otherwise _TypeError_ is thrown.
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### Method extensions
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#### iterator.chain(iterator1[, …iteratorn]) _(es6-iterator/#/chain)_
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Chain multiple iterators into one.
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### Tests [](https://travis-ci.org/medikoo/es6-iterator)
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$ npm test
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