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HashMap Class for JavaScript

Installation

NPM

Using npm:

$ npm install hashmap

Using bower:

$ bower install hashmap

You can download the last stable version from the releases page.

If you like risk, you can download the latest master version, it's usually stable.

To run the tests:

$ npm test

Description

This project provides a HashMap class that works both on Node.js and the browser. HashMap instances store key/value pairs allowing keys of any type.

Unlike regular objects, keys will not be stringified. For example numbers and strings won't be mixed, you can pass Date's, RegExp's, DOM Elements, anything! (even null and undefined)

HashMap constructor overloads

  • new HashMap() creates an empty hashmap
  • new HashMap(map:HashMap) creates a hashmap with the key-value pairs of map
  • new HashMap(arr:Array) creates a hashmap from the 2D key-value array arr, e.g. [['key1','val1'], ['key2','val2']]
  • new HashMap(key:*, value:*, key2:*, value2:*, ...) creates a hashmap with several key-value pairs

HashMap methods

  • get(key:*) : * returns the value stored for that key.
  • set(key:*, value:*) : HashMap stores a key-value pair
  • multi(key:*, value:*, key2:*, value2:*, ...) : HashMap stores several key-value pairs
  • copy(other:HashMap) : HashMap copies all key-value pairs from other to this instance
  • has(key:*) : Boolean returns whether a key is set on the hashmap
  • search(value:*) : * returns key under which given value is stored (null if not found)
  • delete(key:*) : HashMap deletes a key-value pair by key
  • remove(key:*) : HashMap Alias for delete(key:*) (deprecated)
  • type(key:*) : String returns the data type of the provided key (used internally)
  • keys() : Array<*> returns an array with all the registered keys
  • values() : Array<*> returns an array with all the values
  • entries() : Array<[*,*]> returns an array with [key,value] pairs
  • size : Number the amount of key-value pairs
  • count() : Number returns the amount of key-value pairs (deprecated)
  • clear() : HashMap deletes all the key-value pairs on the hashmap
  • clone() : HashMap creates a new hashmap with all the key-value pairs of the original
  • hash(key:*) : String returns the stringified version of a key (used internally)
  • forEach(function(value, key)) : HashMap iterates the pairs and calls the function for each one

Method chaining

All methods that don't return something, will return the HashMap instance to enable chaining.

Examples

Assume this for all examples below

var map = new HashMap();

If you're using this within Node, you first need to import the class

var HashMap = require('hashmap');

Basic use case

map.set("some_key", "some value");
map.get("some_key"); // --> "some value"

Map size / number of elements

var map = new HashMap();
map.set("key1", "val1");
map.set("key2", "val2");
map.size; // -> 2

Deleting key-value pairs

map.set("some_key", "some value");
map.delete("some_key");
map.get("some_key"); // --> undefined

No stringification

map.set("1", "string one");
map.set(1, "number one");
map.get("1"); // --> "string one"

A regular Object used as a map would yield "number one"

Objects as keys

var key = {};
var key2 = {};
map.set(key, 123);
map.set(key2, 321);
map.get(key); // --> 123

A regular Object used as a map would yield 321

Iterating

map.set(1, "test 1");
map.set(2, "test 2");
map.set(3, "test 3");

map.forEach(function(value, key) {
    console.log(key + " : " + value);
});
// ES6 Iterators version
for (const pair of map) {
    console.log(`${pair.key} : ${pair.value}`)
}

Method chaining

map
  .set(1, "test 1")
  .set(2, "test 2")
  .set(3, "test 3")
  .forEach(function(value, key) {
      console.log(key + " : " + value);
  });

LICENSE

The MIT License (MIT)

Copyright (c) 2012 Ariel Flesler

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

To-Do

  • (?) Allow extending the hashing function in a AOP way or by passing a service
  • Make tests work on the browser