every (for Iterators)

Creates a function that reports whether every element of an iterator matches a predicate. Use it with pipe.

const result = pipe(source, every(predicate));

::: info

In ordinary code, prefer the native Iterator.prototype.every: source.every(predicate). Use this es-toolkit/fp/iterator variant when composing transformations with pipe.

:::

Usage

every(predicate)

every is a terminal step: it consumes the iterator until predicate returns a falsy value and reports whether every element matched. It stops pulling at the first non-match, so it can complete on an infinite iterator as long as a non-matching element appears. It delegates to the native Iterator.prototype.every.

import { pipe } from 'es-toolkit/fp';
import { every } from 'es-toolkit/fp/iterator';

// All elements are even.
pipe(
  [2, 4, 6].values(),
  every(x => x % 2 === 0)
);
// Returns: true

// Stops at the first odd element.
pipe(
  [2, 3, 4].values(),
  every(x => x % 2 === 0)
);
// Returns: false

Parameters

• predicate ((value: T, index: number) => unknown): Called with each element and its index; a falsy return short-circuits to false.

Returns

((source: Iterator<T>) => boolean): A function that consumes an iterator and returns whether every element matched.