Customize a Map class in JS

Example 1

// Define a simple Map

Function getMap () {// initialize map _ and add a method to the map _ OBJECT To make map _ look like Map

Var map _ = new Object ();

Map _. put = function (key, value ){

Map _ [key + '_'] = value;

};

Map _. get = function (key ){

Return map _ [key + '_'];

};

Map _. remove = function (key ){

Delete map _ [key + '_'];

};

Map _. keyset = function (){

Var ret = "";

For (var p in map _){

If (typeof p = 'string' & p. substring (p. length-1) = "_"){

Ret + = ",";

Ret + = p. substring (0, p. length-1 );

}

}

If (ret = ""){

Return ret. split (",");

} Else {

Return ret. substring (1). split (",");

}

};

Return map _;

}

Var map = getMap ();

Map. put ("395", ", 89, 35 ");

Map. put ("396", "121111,2222221, 5333332,8444449, 3555555 ");

Alert (map. get ("395"); // output: 12, 21, 35

Alert (map. keyset (); // output: 395,396

Example 2

Function HashMap (){

This. map = {};

}

HashMap. prototype = {

Put: function (key, value ){

This. map [key] = value;

},

Get: function (key ){

If (this. map. hasOwnProperty (key )){

Return this. map [key];

}

Return null;

},

Remove: function (key ){

If (this. map. hasOwnProperty (key )){

Return delete this. map [key];

}

Return false;

},

RemoveAll: function (){

This. map = {};

},

KeySet: function (){

Var _ keys = [];

For (var I in this. map ){

_ Keys. push (I );

}

Return _ keys;

}

};

HashMap. prototype. constructor = HashMap;

Var hashMap = new HashMap ();

HashMap. put ('key', 'value ');

HashMap. put ('key1', 'value ');

Console. log (hashMap. get ('key '));

Console. log (hashMap. keySet ());

Console. log (hashMap. remove ('key '));

Console. log (hashMap. keySet ());

Example 3

Function Map (){
This. elements = new Array ();

// Obtain the number of MAP elements
This. size = function (){
Return this. elements. length;
};

// Determine whether the MAP is empty
This. isEmpty = function (){
Return (this. elements. length <1 );
};

// Delete All MAP elements
This. clear = function (){
This. elements = new Array ();
};

// Add the element (key, value) to the MAP)
This. put = function (_ key, _ value ){
This. elements. push ({
Key: _ key,
Value: _ value
});
};

// Delete the element of the specified KEY. If the KEY is successfully deleted, True is returned. If the KEY fails to be deleted, False is returned.
This. removeByKey = function (_ key ){
Var bln = false;
Try {
For (I = 0; I <this. elements. length; I ++ ){
If (this. elements [I]. key = _ key ){
This. elements. splice (I, 1 );
Return true;
}
}
} Catch (e ){
Bln = false;
}
Return bln;
};

// Delete the element of the specified VALUE. If the element is successfully deleted, True is returned. If the element fails, False is returned.
This. removeByValue = function (_ value) {// removeByValueAndKey
Var bln = false;
Try {
For (I = 0; I <this. elements. length; I ++ ){
If (this. elements [I]. value = _ value ){
This. elements. splice (I, 1 );
Return true;
}
}
} Catch (e ){
Bln = false;
}
Return bln;
};

// Delete the element of the specified VALUE. If the element is successfully deleted, True is returned. If the element fails, False is returned.
This. removeByValueAndKey = function (_ key, _ value ){
Var bln = false;
Try {
For (I = 0; I <this. elements. length; I ++ ){
If (this. elements [I]. value = _ value & this. elements [I]. key = _ key ){
This. elements. splice (I, 1 );
Return true;
}
}
} Catch (e ){
Bln = false;
}
Return bln;
};

// Obtain the element VALUE of the specified KEY. If the VALUE fails, NULL is returned.
This. get = function (_ key ){
Try {
For (I = 0; I <this. elements. length; I ++ ){
If (this. elements [I]. key = _ key ){
Return this. elements [I]. value;
}
}
} Catch (e ){
Return false;
}
Return false;
};

// Obtain the elements of the specified index (using element. key, element. value to obtain KEY and VALUE). If the index fails, NULL is returned.
This. element = function (_ index ){
If (_ index <0 | _ index> = this. elements. length ){
Return null;
}
Return this. elements [_ index];
};

// Determine whether the MAP contains the specified KEY element.
This. containsKey = function (_ key ){
Var bln = false;
Try {
For (I = 0; I <this. elements. length; I ++ ){
If (this. elements [I]. key = _ key ){
Bln = true;
}
}
} Catch (e ){
Bln = false;
}
Return bln;
};

// Determine whether the MAP contains the specified VALUE element.
This. containsValue = function (_ value ){
Var bln = false;
Try {
For (I = 0; I <this. elements. length; I ++ ){
If (this. elements [I]. value = _ value ){
Bln = true;
}
}
} Catch (e ){
Bln = false;
}
Return bln;
};

// Determine whether the MAP contains the specified VALUE element.
This. containsObj = function (_ key, _ value ){
Var bln = false;
Try {
For (I = 0; I <this. elements. length; I ++ ){
If (this. elements [I]. value = _ value & this. elements [I]. key = _ key ){
Bln = true;
}
}
} Catch (e ){
Bln = false;
}
Return bln;
};

// Obtain the ARRAY (ARRAY) of all values in the MAP)
This. values = function (){
Var arr = new Array ();
For (I = 0; I <this. elements. length; I ++ ){
Arr. push (this. elements [I]. value );
}
Return arr;
};

// Obtain the ARRAY (ARRAY) of all values in the MAP)
This. valuesByKey = function (_ key ){
Var arr = new Array ();
For (I = 0; I <this. elements. length; I ++ ){
If (this. elements [I]. key = _ key ){
Arr. push (this. elements [I]. value );
}
}
Return arr;
};

// Obtain the ARRAY (ARRAY) of all keys in the MAP)
This. keys = function (){
Var arr = new Array ();
For (I = 0; I <this. elements. length; I ++ ){
Arr. push (this. elements [I]. key );
}
Return arr;
};

// Get key through value
This. keysByValue = function (_ value ){
Var arr = new Array ();
For (I = 0; I <this. elements. length; I ++ ){
If (_ value = this. elements [I]. value ){
Arr. push (this. elements [I]. key );
}
}
Return arr;
};

// Obtain the ARRAY (ARRAY) of all keys in the MAP)
This. keysRemoveDuplicate = function (){
Var arr = new Array ();
For (I = 0; I <this. elements. length; I ++ ){
Var flag = true;
For (var j = 0; j if (arr [j] = this. elements [I]. key ){
Flag = false;
Break;
}
}
If (flag ){
Arr. push (this. elements [I]. key );
}
}
Return arr;
};
}

The second method is easy to use. I recommend the second method.