join (Functional Programming)

Creates a function that joins array values into a string. Use it with pipe.

const result = pipe(array, join(separator));

::: info

This helper is specific to es-toolkit/fp. Use it when you want this operation as part of a pipe pipeline.

:::

Usage

join converts the piped array to a string by joining its values with separator. When separator is omitted, it uses a comma.

import { join, pipe } from 'es-toolkit/fp';

pipe(['a', 'b', 'c'], join('-')); // => 'a-b-c'

pipe(['a', 'b', 'c'], join()); // => 'a,b,c'

Parameters

• separator (string, optional): The string inserted between values. Defaults to ,.

Returns

((array: readonly T[]) => string): A function that maps a readonly T[] to a joined string.