Array/Since 1.38.0

partition

Splits an array into two arrays based on whether each element satisfies a predicate function.

partition(array, predicate):[T[], T[]]

Parameters

arrayT[]required

The array whose elements should be divided into two groups.

predicate(item: T) => booleanrequired

A function that determines which group each element belongs to. Elements returning true are placed in the first array, while elements returning false are placed in the second array.

Returns

[T[], T[]]

A tuple containing two arrays: the first contains elements for which the predicate returned true, and the second contains elements for which it returned false.

Examples

Basic usage

Separate numbers into even and odd groups.

TypeScript

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

const numbers = [1, 2, 3, 4, 5, 6];

const [even, odd] = partition(
  numbers,
  (item) => item % 2 === 0,
);

console.log(even);
// [2, 4, 6]

console.log(odd);
// [1, 3, 5]

Partition objects

Partition objects based on a property or condition.

TypeScript

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

const users = [
  { name: "Amir", active: true },
  { name: "Sara", active: false },
  { name: "Reza", active: true },
];

const [activeUsers, inactiveUsers] = partition(
  users,
  (user) => user.active,
);

console.log(activeUsers);
// [
//   { name: "Amir", active: true },
//   { name: "Reza", active: true },
// ]

console.log(inactiveUsers);
// [
//   { name: "Sara", active: false },
// ]

Predicate returns false

Elements that do not satisfy the predicate are placed in the second array.

TypeScript

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

const numbers = [1, 2, 3, 4];

const result = partition(
  numbers,
  (item) => item > 10,
);

console.log(result);
// [[], [1, 2, 3, 4]]

Empty array

An empty array produces two empty arrays.

TypeScript

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

const result = partition(
  [],
  (item) => item > 0,
);

console.log(result);
// [[], []]

Built with@cyref/js·Official documentation