fill (Lodash Compatibility)

Use fill from es-toolkit

This fill function operates with complex behavior due to handling null or undefined, support for array-like objects, etc.

Instead, use the faster and more modern fill from es-toolkit.

Fills the elements of an array with a specified value.

const result = fill(array, value, start, end);

Reference

fill(array, value, start?, end?)

Use fill when you want to fill a specific range or the entire array with the same value. It modifies the original array directly.

import { fill } from 'es-toolkit/compat';

// Fill entire array
const arr1 = [1, 2, 3];
fill(arr1, 'a');
// Returns: ['a', 'a', 'a']

// Fill specific range
const arr2 = [1, 2, 3, 4, 5];
fill(arr2, '*', 1, 4);
// Returns: [1, '*', '*', '*', 5]

// Use negative indices
const arr3 = [1, 2, 3, 4, 5];
fill(arr3, 'x', -3, -1);
// Returns: [1, 2, 'x', 'x', 5]

Array-like objects are also supported.

import { fill } from 'es-toolkit/compat';

const arrayLike = { 0: 1, 1: 2, 2: 3, length: 3 };
fill(arrayLike, 'a', 1, 2);
// Returns: { 0: 1, 1: 'a', 2: 3, length: 3 }

null or undefined arrays are treated as empty arrays.

import { fill } from 'es-toolkit/compat';

fill(null, 'a');
// Returns: []

fill(undefined, 'a');
// Returns: []

Strings are read-only, so they are returned as is.

import { fill } from 'es-toolkit/compat';

fill('abc', 'x');
// Returns: 'abc' (not modified)

Parameters

• array (ArrayLike<T> | null | undefined): The array to fill.
• value (U): The value to fill the array with.
• start (number, optional): The start position. Defaults to 0.
• end (number, optional): The end position (not included). Defaults to array.length.

Returns

(ArrayLike<T | U>): Returns the array filled with the value.