Implement your own Map object in JavaScript

 

HashMap plays an irreplaceable role in programming. It provides data storage and reading methods such as m. put (key, value); m. get (key);, which is very convenient. However, such an object is not provided in JavaScript (HTML4.0. The following code is used to create a Map object. I have been using it for many years and it works well for your reference.

 

 

 

1. Map source code

 

 

/** Map is a general map object for storing key value pairs

* @ Param m-default set of properties

*/

Var Map = function (m ){

Var map;

If (typeof m = 'undefined') map = new Array ();

Else map = m;

/**

* Get a list of the keys to check

*/

This. keys = function (){

Var _ keys = new Array ();

For (var _ I in map ){

_ Keys. push (_ I );

}

Return _ keys ;//

};

/**

* Put stores the value in the table

* @ Param key the index in the table where the value will be stored

* @ Param value the value to be stored

*/

This. put = function (key, value ){

Map [key] = value;

};

/**

* Return the value stored in the table

* @ Param key the index of the value to retrieve

*/

This. get = function (key ){

Return map [key];

};

/**

* Remove the value from the table

* @ Param key the index of the value to be removed

*/

This. remove = function (key ){

Map [key] = null;

Delete map [key];

};

/**

* Clear the table

*/

This. clear = function (){

Delete map;

Map = new Array ();

};

}

 

 

 

2. Create a Map object

 

Var m = new Map ();

 

M. put ("id", "1000 ");

 

M. put ("name", "James ");

 

 

 

3. Use www.2cto.com

 

<Div id = "testMap" '> </div>

 

<Script type = 'text/javascript '>

 

Document. getElementById ("testMap"). innerHTML = m. get ("name ");

 

</Script>

 

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