Fast Map extension for Node.js & The Browser
LightMap
LightMap is an extension of Map that adds iterative extensions to Map like map, filter, reduce, sort, etc.
Installation
npm i @parellin/lightmap
Usage
Basic usage:
const LightMap = require( '@parellin/lightmap' );
const x = new LightMap( [ [ 'a', 'hello' ], [ 'b', 'world' ] ] );
// LightMap { 'a' => 'hello', 'b' => 'world' }
Map usage:
For standard Map usage please refer to MDN Web Docs
.filter:
Filter LightMap based on keys and values based in. Comparisons can be made on the key and/or value.
const x = new LightMap( [ [ 'a', 'hello' ], [ 'b', 'world' ] ] );
x.filter( ( val, key ) => {
return key === 'a';
} );
// LightMap { 'a' => 'hello' }
.map:
Map LightMap with new key and/or value.
Return the new item in a "tuple" form matching the Map paradigm ([ x, y ]).
const x = new LightMap( [ [ 'a', 10 ], [ 'b', 20 ] ] );
x.map( ( val, key ) => {
return [ key, val + 10 ];
} );
// LightMap { 'a' => 20, 'b' => 30 }
.reduce:
Reduce LightMap with new value. Must return the carriage value just like Array.reduce.
const x = new LightMap( [ [ 'a', 'hello' ], [ 'b', 'world' ] ] );
x.reduce( ( r, [ key, val ] ) => {
r += val + ' ';
return r;
}, '' );
// hello world
.sortKeys:
Map LightMap with sorted key-value pairs.
const x = new LightMap( [ [ 'b', 'world' ], [ 'a', 'hello' ] ] );
x.sortKeys()
// LightMap { 'a' => 'hello', 'b' => 'world' }
.sortValues:
Map LightMap with sorted key-value pairs sorted by value.
const x = new LightMap( [ [ 'a', 10 ], [ 'b', 5 ], [ 'c', 1 ] ] );
x.sortValues( ( a, b ) => a >= b )
// LightMap { 'c' => 1, 'b' => 5, 'a' => 10 }
x.sortValues( ( a, b ) => a <= b )
// LightMap { 'a' => 10, 'b' => 5, 'c' => 1 }
.mapToArray:
maps a LightMap object to an array of arrays in the Map Pattern (re-constructable pattern)
const x = new LightMap( [ [ 'a', 0 ], [ 'b', 1 ] ] );
x.mapToArray();
// [ [ 'a', 0 ], [ 'b', 1 ] ]
.toJSON:
Native class override - returns .mapToArray method
const x = new LightMap( [ [ 'a', 0 ], [ 'b', 1 ] ] );
x.toJSON();
// [ [ 'a', 0 ], [ 'b', 1 ] ]
.toString:
Native class override - returns JSON stringified .mapToArray
const x = new LightMap( [ [ 'a', 0 ], [ 'b', 1 ] ] );
x.toString();
// [["a",0],["b",1]]
.indexOf:
returns the first index at which a given element can be found in the array, or -1 if it is not present
const x = new LightMap( [ [ 'a', 0 ], [ 'b', 1 ] ] );
x.indexOf( 'b' );
// 1
[ Symbol.replace ]:
symbol specifies the method that replaces matched substrings of a string
const x = new LightMap( [ [ '{{ a }}', 'hello' ], [ '{{ b }}', 'world' ] ] );
'{{ a }} {{ b }}'.replace( x );
// hello world
[ Symbol.toPrimitive( string ) ]:
symbol that specifies a function valued property that is called to convert an object to a primitive value
const x = new LightMap( [ [ 'a', 0 ], [ 'b', 1 ] ] );
'' + x;
// [["a",0],["b",1]]
[ Symbol.toPrimitive( number ) ]:
symbol that specifies a function valued property that is called to convert an object to a primitive value
const x = new LightMap( [ [ 'a', 0 ], [ 'b', 1 ] ] );
+x;
// 2 (size of the Map)