@mi-sec/lightmap
Version:
Extension of Map - adds iterative extensions to Map like map, filter, reduce, sort, etc.
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Markdown
<p align="center">
<img src="https://repository-images.githubusercontent.com/136985658/d04d2300-8125-11e9-8377-864d0542984f"
alt="LightMap"
width="300px"
/>
</p>
<p align="center">Fast Map extension for Node.js & The Browser</p>
# LightMap
LightMap is an extension of Map that adds iterative extensions to Map like `map`, `filter`, `reduce`, `sort`, etc.
[](https://www.npmjs.com/package/@mi-sec/lightmap)
### Installation
`npm i @mi-sec/lightmap`
### Usage
**Basic usage:**
```
const LightMap = require( '@mi-sec/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](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map)
**`.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)
```