Map anything 🗺

npm i map-anything

Array.map but for objects with good TypeScript support. A small and simple integration.

Motivation

I always want to do:

someObject.map((val) => someFunction)

But this doesn't exist for objects, you need to do this instead:

Object.entries(someObject).reduce((carry, [key, value], index, array) => {
  carry[key] = someFunction(value, key, array)
  return carry
}, {})

So I made a wrapper function for that. 😃

map-anything has very good #TypeScript support as well.

Usage

Provided Functions:

• mapObject takes an object and maps over the values of each key
• mapObjectAsync takes an object and maps a promise over the values of each key, after which you can just do a single await
• mapMap takes a map and maps over the values of each key

Basic Usage

import { mapObject } from 'map-anything'

const pokemon = {
  '001': { name: 'Bulbasaur', level: 10 },
  '004': { name: 'Charmander', level: 8 },
  '007': { name: 'Squirtle', level: 11 },
}

const levelUp = mapObject(pokemon, (pkmn) => {
  return { ...pkmn, level: pkmn.level + 1 }
})

// results in:
levelUp ===
  {
    '001': { name: 'Bulbasaur', level: 11 },
    '004': { name: 'Charmander', level: 9 },
    '007': { name: 'Squirtle', level: 12 },
  }

Access the propName in the map function

A function passed to Array.map will get the value as first argument and an index as second. With mapObject you will get the propName as second argument.

import { mapObject } from 'map-anything'

const pokemon = {
  '001': { name: 'Bulbasaur', level: 10 },
  '004': { name: 'Charmander', level: 8 },
  '007': { name: 'Squirtle', level: 11 },
}

const addIds = mapObject(pokemon, (pkmn, propName) => {
  const id = propName
  return { ...pkmn, id }
})

// results in:
addIds ===
  {
    '001': { name: 'Bulbasaur', level: 10, id: '001' },
    '004': { name: 'Charmander', level: 8, id: '004' },
    '007': { name: 'Squirtle', level: 11, id: '007' },
  }

Map Object Async

const pokemon = {
  '001': { name: 'Bulbasaur', level: 10 },
  '004': { name: 'Charmander', level: 8 },
  '007': { name: 'Squirtle', level: 11 },
}

const result = await mapObjectAsync(pokemon, async (pkmn, propName) => {
  const id = propName
  const data = await fetchData(id) // hypothetical API call
  return { ...pkmn, data }
})

// results in:
result ===
  {
    '001': { name: 'Bulbasaur', level: 10, data: '...' }, // some fetched data
    '004': { name: 'Charmander', level: 8, data: '...' },
    '007': { name: 'Squirtle', level: 11, data: '...' },
  }

TypeScript

Without having to specify the return type in the reducer, I've set map-anything up so it automatically detects that type for you!

Meet the family (more tiny utils with TS support)

• is-what 🙉
• is-where 🙈
• merge-anything 🥡
• check-anything 👁
• remove-anything ✂️
• getorset-anything 🐊
• map-anything 🗺
• filter-anything ⚔️
• copy-anything 🎭
• case-anything 🐫
• flatten-anything 🏏
• nestify-anything 🧅

Source code

The source code is rather simple, it's doing something like the snippet show here below. However, it's adding amazing typescript.

function mapObject (object, fn) {
  return Object.entries(object)
    .reduce((carry, [key, value], index, array) => {
      carry[key] = fn(value, key, array)
      return carry
    }, {})
}