map-object-util

A TypeScript utility function that transforms objects into arrays with type safety.

Installation

npm install map-object-util

Usage

import { mapObject } from 'map-object-util';

// Define your data types
interface Person {
  name: string;
  age: number;
}

// Create an object with typed data
const persons: Record<string, Person> = {
  "P-1000001": {
    name: "John Doe",
    age: 30,
  },
  "P-1000002": {
    name: "Jane Smith",
    age: 25,
  },
};

// Transform with explicit type parameters
const result = mapObject<Person, "personId">(persons, "personId");
// TypeScript properly infers: Array<Person & { personId: string }>

// Type-safe access to properties
console.log(result[0].personId); // "P-1000001"
console.log(result[0].name);     // "John Doe"
console.log(result[0].age);      // 30

API

mapObject<T, K>(obj, keyName)

Transforms an object into an array of objects where each item contains a key-value pair from the original object plus its properties.

Type Parameters:

• T - The type of values in the source object
• K extends string = "key" - The type of the key name to use in result objects

Parameters:

• obj: Record<string, T> - The source object to transform
• keyName: K = "key" - The name to use for the key in the resulting objects

Returns:

• Array<T & { [P in K]: string }> - An array of objects containing the key and all properties from the source object

Type Helper

import { MapObjectResult } from 'map-object-util';

// Define a typed result
type PersonWithId = MapObjectResult<Person, "personId">;

License

MIT# map-obect-util