leonardoraele/map-obj

Fork of map-obj to add { path } information to the mapper function.

map-obj

Map object keys and values into a new object

Install

npm install map-obj

Usage

import mapObject, {mapObjectSkip} from 'map-obj';

const newObject = mapObject({foo: 'bar'}, (key, value) => [value, key]);
//=> {bar: 'foo'}

const newObject = mapObject({FOO: true, bAr: {bAz: true}}, (key, value) => [key.toLowerCase(), value]);
//=> {foo: true, bar: {bAz: true}}

const newObject = mapObject({FOO: true, bAr: {bAz: true}}, (key, value) => [key.toLowerCase(), value], {deep: true});
//=> {foo: true, bar: {baz: true}}

const newObject = mapObject({one: 1, two: 2}, (key, value) => value === 1 ? [key, value] : mapObjectSkip);
//=> {one: 1}

API

mapObject(source, mapper, options?)

source

Type: object

The source object to copy properties from.

mapper

Type: (sourceKey, sourceValue, source, path) => [targetKey, targetValue, mapperOptions?] | mapObjectSkip

A mapping function.

path

Type: string[]

When using {deep: true}, this is the sequence of keys to reach the current value from the source, otherwise it is an empty array.

For arrays, the key is the index of the element being mapped.

Example:

import mapObject from 'map-obj';

const originalObject = {first: [{value: 1}, {value: 2}, {value: 3}], second: [{value: 4}, {value: 5}, {value: 6}]};

const mapper = (key, value, source, path) => path.includes('first') || path.includes(1)
	? [`__${key}__`, value]
	: [key, value];

const newObject = mapObject(originalObject, mapper, {deep: true});
//=> {__first__: [{__value__: 1}, {__value__: 2}, {__value__: 3}], second: [{value: 4}, {__value__: 5}, {value: 6}]}

mapperOptions

Type: object

shouldRecurse

Type: boolean
Default: true

Whether targetValue should be recursed.

Requires deep: true.

options

Type: object

deep

Type: boolean
Default: false

Recurse nested objects and objects in arrays.

target

Type: object
Default: {}

The target object to map properties on to.

mapObjectSkip

Return this value from a mapper function to exclude the key from the new object.

import mapObject, {mapObjectSkip} from 'map-obj';

const object = {one: 1, two: 2}
const mapper = (key, value) => value === 1 ? [key, value] : mapObjectSkip
const result = mapObject(object, mapper);

console.log(result);
//=> {one: 1}

Related

• filter-obj - Filter object keys and values into a new object

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