Define Map Utilities

Flexible mapping of data dictionaries (arrays of objects) to other formats.

defineMap

Transforms an array of objects into an array, or a record (map) keyed by one of the object's properties.

Usage

import { defineMap } from '@preflower/utils'

const userList = [
  { id: 1, name: 'Alice', age: 25 },
  { id: 2, name: 'Bob', age: 30 }
]

// 1. Get an array of specific keys
const ids = defineMap(userList, 'id') 
// [1, 2]

// 2. Map keyed by ID to a specific property
const nameMap = defineMap(userList, 'id', 'name') 
// { 1: 'Alice', 2: 'Bob' }

// 3. Map keyed by ID to multiple properties (Pick)
const detailMap = defineMap(userList, 'id', ['name', 'age']) 
// { 1: { name: 'Alice', age: 25 }, 2: { name: 'Bob', age: 30 } }

Type Definition

This function is overloaded to provide strong typing for different use cases.

Parameters

Name	Type	Description	Default
defs	T[]	Array of objects to transform.	-
key	K	The property to use as the base for mapping.	-
values	V | V[]	The properties to include in the resulting map or array.	undefined