map-anything

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.

Meet the family

• copy-anything 🎭
• merge-anything 🥡
• filter-anything ⚔️
• find-and-replace-anything 🎣
• compare-anything 🛰
• flatten-anything 🏏
• is-what 🙉

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 }
})

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

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

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!

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
    }, {})
}