mapKeys

Map over the keys of an object

Usage

Given an object and a toKey callback function, returns a new object with all the keys mapped through the toKey function. The callback is given both the key and value for each entry.

import * as 
import _
_ from 'radashi'

const 
const ra: {
    mode: string;
    power: string;
}
ra = {
  
mode: string
mode: 'god',
  
power: string
power: 'sun',
}

import _
_.
function mapKeys<string, "mode" | "power", string>(obj: Record<"mode" | "power", string>, mapFunc: (key: "mode" | "power", value: string) => string): Record<string, string>
Map over all the keys of an object to return a new object.
@see ― https://radashi.js.org/reference/object/mapKeys
@example 
const a = { a: 1, b: 2, c: 3 }
mapKeys(a, (key, value) => key + value)
// => { a1: 1, b2: 2, c3: 3 }
@version ― 12.1.0
mapKeys(
const ra: {
    mode: string;
    power: string;
}
ra, 
key: "mode" | "power"
key => 
key: "mode" | "power"
key.
String.toUpperCase(): string
Converts all the alphabetic characters in a string to uppercase.
toUpperCase()) // => { MODE, POWER }
import _
_.
function mapKeys<string, "mode" | "power", string>(obj: Record<"mode" | "power", string>, mapFunc: (key: "mode" | "power", value: string) => string): Record<string, string>
Map over all the keys of an object to return a new object.
@see ― https://radashi.js.org/reference/object/mapKeys
@example 
const a = { a: 1, b: 2, c: 3 }
mapKeys(a, (key, value) => key + value)
// => { a1: 1, b2: 2, c3: 3 }
@version ― 12.1.0
mapKeys(
const ra: {
    mode: string;
    power: string;
}
ra, (
key: "mode" | "power"
key, 
value: string
value) => 
value: string
value) // => { god: 'god', power: 'power' }

Type-safe alternatives

If your goal is to uppercase or lowercase the keys of an object, Radashi provides purpose-built functions for that, called upperize and lowerize. These functions have better type inference than mapKeys.

import * as _ from 'radashi'

const ra = {
  mode: 'god',
  power: 'sun',
}

const upperized = _.upperize(ra)
//    ^? { MODE: string, POWER: string }

const lowerized = _.lowerize(upperized)
//    ^? { mode: string, power: string }