ht

Hash Table Implementation for javascript

npm install ht
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Build Status

browser support

ht

ht is a HashTable implementation in javascript that can be used in both node and the browser.

Installation

npm install ht

Or download the source (minified)

Note ht depends on declare.js, extended, is-extended, and array-extended

Usage

To create a new HashTable

var Ht = require("ht");
var ht = new Ht();

put(key, value)

Adds a new key value pair to the hash table, ht supports any value as a key.

var key = {}, key2 = {};
ht.put(key, "value1");
ht.put(key2, "value2");

ht.get(key); //"value1";
ht.get(key2); //"value2";

If your key contains a hashCode, function then that will be used to put the key value pair into the hash table.

function Person(first, last){
    this.firstName = first;
    this.lastName = last;
}

Person.prototype.hashCode = function(){
    return this.firstName + this.lastName;
}

ht.put(new Person("bob", "yukon"), "this is bob");
ht.put(new Person("sally", "yukon"), "this is sally");

ht.get(new Person("bob", "yukon")); //"this is bob"

get(key)

Get a a value based on the key.

ht.put(new Date(2013, 1, 22), "value1");
ht.put(new Date(2013, 1, 23), "value2");

ht.get(new Date(2013, 1, 22)); //"value1";
ht.get(new Date(2013, 1, 23); //"value2";

set(key)

Set a a value based on the key.

ht.put(new Date(2013, 1, 22), "value1");
ht.put(new Date(2013, 1, 23), "value2");

ht.get(new Date(2013, 1, 22)); //"value1";
ht.get(new Date(2013, 1, 23); //"value2";

ht.set(new Date(2013, 1, 22), "new value1");
ht.set(new Date(2013, 1, 23), "new value2");

ht.get(new Date(2013, 1, 22)); //"new value1";
ht.get(new Date(2013, 1, 23); //"new value2";

remove(key)

Removes a key value pair.

ht.put(new Date(2013, 1, 22), "value1");
ht.put(new Date(2013, 1, 23), "value2");

ht.get(new Date(2013, 1, 22)); //"value1";
ht.get(new Date(2013, 1, 23); //"value2";

ht.remove(new Date(2013, 1, 22)); //"value1";
ht.remove(new Date(2013, 1, 23); //"value2";

ht.get(new Date(2013, 1, 22)); //null;
ht.get(new Date(2013, 1, 23); //null";

contains(key)

Returns true or false if the table does or does not contain a given key value pair.


ht.put(new Date(2013, 1, 22), "value1");
ht.put(new Date(2013, 1, 23), "value2");

ht.contains(new Date(2013, 1, 22)); //true;
ht.contains(new Date(2013, 1, 23); //true;

concat(hashTable

Concats two hash tables together into a new one.


var ht1 = new Ht(), ht2 = new Ht();

ht1.put(new Date(2013, 1, 22), "value1");
ht1.put(new Date(2013, 1, 23), "value2");

var key = {}, key2 = {};
ht2.put(key, "value1");
ht2.put(key2, "value2");

var ht3 = ht1.concat(ht2);

ht3.contains(key); //true
ht3.contains(key2); //true
ht1.contains(new Date(2013, 1, 22)); //true
ht1.contains(new Date(2013, 1, 23)); //true

clear

Clear all items from the hash table

ht.put("key1", "value1");
ht.put("key2", "value2");

ht.clear();

ht.contains("key1"); //false
ht.contains("key2"); //false

keys

Returns an array of all keys in the table.

ht.put("key1", "value1");
ht.put("key2", "value2");

ht.keys(); //["key1", "key2"]

values

Gets all values in the hash table.

ht.put("key1", "value1");
ht.put("key2", "value2");

ht.values(); //["value1", "value2"]

entrySet

Returns an array of all key value pairs in the table.

ht.put("key1", "value1");
ht.put("key2", "value2");

ht.entrySet(); //[{key: "key1", value: "value1"}, {key: "key2", value: "value2"}]

isEmpty

Returns true if the table contains any values, false otherwise.


var ht = new Ht();

ht.isEmpty(); //true

ht.put("key1", "value1");
ht.put("key2", "value2");

ht.isEmpty(); //false

Array methods.

Each hash table contains the following array like methods.

Note each method will pass a key and value to the iterator instead of a value and index.


ht.put("key1", "value1");
ht.put("key2", "value2");

ht.forEach(function(key, value){
    console.log(key + " : " + value);
});
  • forEach
  • filter
  • map
  • every
  • some
  • reduce
  • reduceRight
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