Array/Since 1.38.0

keyBy

Converts an array of objects into an object keyed by the value of a specified property.

keyBy(array, key):Record<string, T>

Parameters

arrayT[]required

The array of objects to convert into a keyed object.

keyKrequired

The property key whose value is used as the key in the resulting object.

Returns

Record<string, T>

An object where each key is created from the specified property value and maps to the corresponding array element.

Examples

Basic usage

Create an object keyed by the id property of each item.

TypeScript

import { keyBy } from "@cyref/js";

const users = [
  { id: "1", name: "Amir" },
  { id: "2", name: "Sara" },
  { id: "3", name: "Reza" },
];

const result = keyBy(users, "id");

console.log(result);
// {
//   "1": { id: "1", name: "Amir" },
//   "2": { id: "2", name: "Sara" },
//   "3": { id: "3", name: "Reza" },
// }

Using another property

The key can be any property available on the object type.

TypeScript

import { keyBy } from "@cyref/js";

const products = [
  { sku: "LP-01", name: "Laptop" },
  { sku: "PH-01", name: "Phone" },
  { sku: "TB-01", name: "Tablet" },
];

const result = keyBy(products, "sku");

console.log(result);
// {
//   "LP-01": { sku: "LP-01", name: "Laptop" },
//   "PH-01": { sku: "PH-01", name: "Phone" },
//   "TB-01": { sku: "TB-01", name: "Tablet" },
// }

Duplicate keys

If multiple elements have the same key value, the later element replaces the previous element.

TypeScript

import { keyBy } from "@cyref/js";

const users = [
  { id: "1", name: "Amir" },
  { id: "2", name: "Sara" },
  { id: "1", name: "Reza" },
];

const result = keyBy(users, "id");

console.log(result);
// {
//   "1": { id: "1", name: "Reza" },
//   "2": { id: "2", name: "Sara" },
// }

Empty array

An empty array produces an empty object.

TypeScript

import { keyBy } from "@cyref/js";

const result = keyBy([], "id");

console.log(result);
// {}

Built with@cyref/js·Official documentation