Multimap - Map which Allow Multiple Values for the same Key


Install

``bash
npm install multimap --save
`

Usage


If you'd like to use native version when it exists and fallback to polyfill if it doesn't, but without implementing Map on global scope, do:

`javascript
var Multimap = require('multimap');
var m = new Multimap();
`

If the global es6 Map exists or Multimap.Map is set, Multimap will use the Map as inner store, that means Object can be used as key.

`javascript
var Multimap = require('multimap');

// if harmony is on
/ nothing need to do /
// or if you are using es6-shim
Multimap.Map = ShimMap;

var m = new Multimap();
var key = {};
m.set(key, 'one');

`

Otherwise, an object will be used, all the keys will be transformed into string.

$3

Just download the index.js as Multimap.js.

`


`

Or use as an AMD loader:

`
require(['./Multimap.js'], function (Multimap) {
var map = new Multimap([['a', 1], ['b', 2], ['c', 3]]);
map = map.set('b', 20);
map.get('b'); // [2, 20]
});
`

* Browsers should support Object.defineProperty and Array.prototype.forEach.

API

Following shows how to use Multimap:

`javascript
var Multimap = require('multimap');

var map = new Multimap([['a', 'one'], ['b', 1], ['a', 'two'], ['b', 2]]);

map.size; // 4
map.count; // 2

map.get('a'); // ['one', 'two']
map.get('b'); // [1, 2]

map.has('a'); // true
map.has('foo'); // false

map.has('a', 'one'); // true
map.has('b', 3); // false

map.set('a', 'three');
map.size; // 5
map.count; // 2
map.get('a'); // ['one', 'two', 'three']

map.set('b', 3, 4);
map.size; // 7
map.count; // 2

map.delete('a', 'three'); // true
map.delete('x'); // false
map.delete('a', 'four'); // false
map.delete('b'); // true

map.size; // 2
map.count; // 1

map.set('b', 1, 2);
map.size; // 4
map.count; // 2


map.forEach(function (value, key) {
// iterates { 'one', 'a' }, { 'two', 'a' }, { 1, b }, { 2, 'b' }
});

map.forEachEntry(function (entry, key) {
// iterates {['one', 'two'], 'a' }, {[1, 2], 'b' }
});


var keys = map.keys(); // iterator with ['a', 'b']
keys.next().value; // 'a'
var values = map.values(); // iterator ['one', 'two', 1, 2]

map.clear(); // undefined
map.size; // 0
map.count; // 0
``

License

(The MIT License)

Copyright (c) 2013, Villa.Gao ;
All rights reserved.