map-map

map-map

Applies a callback to each key-value pair of a Map, Object, or other collection. The original collection is not modified; a copy is returned.

Installation

Requires Node.js 7.0.0 or above.

npm i map-map

API

The module exports a single function.

Parameters

1. Bindable: map (Array, iterator, Object, Map, Set, string, or Typed Array)
2. mapper (function): The callback which receives three arguments (key, value, and index) and which returns a two-element array containing the new key and value.
3. Optional: options: Object argument which is forwarded to entries-array, a dependency of this module.

Return Value

A copy of map which has had mapper applied to each of its key-value pairs.

Example

const mapMap = require('map-map')

let map = new Map([['key', 'value']])
map = mapMap(map, (key, value, index) => [key + '_mapped', value + '_mapped'])
map.get('key_mapped') // 'value_mapped'

Works on Objects too:

const mapMap = require('map-map')

let obj = {key: 'value'}
obj = mapMap(obj, (key, value, index) => [key + '_mapped', value + '_mapped'])
obj.key_mapped // 'value_mapped'