arrayToHash

Converts an array of objects into a hash map (plain object) keyed by a specified property. Useful for fast lookups by a unique identifier.

Import

import { arrayToHash } from "1o1-utils";

import { arrayToHash } from "1o1-utils/array-to-hash";

Signature

function arrayToHash<T>({ array, key }: ArrayToHashParams<T>): Record<string, T>

Parameters

Name	Type	Required	Description
array	T[]	Yes	The array of objects to convert
key	keyof T	Yes	The property to use as hash key

Returns

Record<string, T> — An object keyed by the specified property.

Examples

const users = [
  { id: "a1", name: "Alice" },
  { id: "b2", name: "Bob" },
];

arrayToHash({ array: users, key: "id" });
// => { a1: { id: "a1", name: "Alice" }, b2: { id: "b2", name: "Bob" } }

Edge Cases

• Throws if array is not an array.
• Throws if key is not a string.
• Skips items where the key value is falsy or not a string.

Also known as

array to object, keyBy, objectify, index by, lookup table, dictionary

Prompt suggestion

I'm using 1o1-utils (npm: https://www.npmjs.com/package/1o1-utils, GitHub: https://github.com/pedrotroccoli/1o1-utils, LLM context: https://pedrotroccoli.github.io/1o1-utils/llms.txt). Show me how to use arrayToHash to create a lookup table from an API response array