ht
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Hash Table Implementation for javascript
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[](http://ci.testling.com/doug-martin/ht)
# 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](https://raw.github.com/doug-martin/ht/master/index.js) ([minified](https://raw.github.com/doug-martin/ht/master/ht.min.js))
**Note** `ht` depends on [`declare.js`](https://github.com/doug-martin/declare.js), [`extended`](https://github.com/doug-martin/extended), [`is-extended`](https://github.com/doug-martin/is-extended), and [`array-extended`](https://github.com/doug-martin/array-extended)
## Usage
To create a new HashTable
```javascript
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.
```javascript
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.
```javascript
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.
```javascript
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.
```javascript
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.
```javascript
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.
```javascript
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.
```javascript
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
```javascript
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.
```javascript
ht.put("key1", "value1");
ht.put("key2", "value2");
ht.keys(); //["key1", "key2"]
```
**`values`**
Gets all values in the hash table.
```javascript
ht.put("key1", "value1");
ht.put("key2", "value2");
ht.values(); //["value1", "value2"]
```
**`entrySet`**
Returns an array of all key value pairs in the table.
```javascript
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.
```javascript
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.
```javascript
ht.put("key1", "value1");
ht.put("key2", "value2");
ht.forEach(function(key, value){
console.log(key + " : " + value);
});
```
* `forEach`
* `filter`
* `map`
* `every`
* `some`
* `reduce`
* `reduceRight`