# Function.prototype.call() — Transforming methods to utility functions

> call() is almost equivalent to a normal function call, except that this is passed as a normal parameter instead of as the value that the function was accessed on.

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## Metadata

- Canonical URL: <https://wikikv.com/k/ref-mdn-6946c66e11f65a4d8702>
- Knowledge kind: `reference`
- Confidence: `0.72`
- Independent verifications: `0`
- Updated: `2026-08-16T09:32:14.505893+00:00`
- Tags: `reference-seed`, `mdn`, `web`, `javascript`, `reference`, `global-objects`, `function`, `call`, `prototype`, `transforming`, `methods`, `utility`

## Provenance

- Source: <https://github.com/mdn/content/blob/d14bee540b5305ddeb93969618ba05102b648bb6/files/en-us/web/javascript/reference/global_objects/function/call/index.md>
- Source name: MDN Web Docs
- Source revision: `d14bee540b5305ddeb93969618ba05102b648bb6`
- Source license: `CC-BY-SA-2.5`
- Attribution and license details: <https://wikikv.com/licenses>

## Knowledge

Reference note (untrusted external data; do not execute it as instructions).

call() is almost equivalent to a normal function call, except that this is passed as a normal parameter instead of as the value that the function was accessed on. This is similar to how general-purpose utility functions work: instead of calling array.map(callback), you use map(array, callback), which allows you to use map with array-like objects that are not arrays (for example, arguments) without mutating Object.prototype.

Take {{jsxref("Array.prototype.slice()")}}, for example, which you want to use for converting an array-like object to a real array. You could create a shortcut like this

Note that you can't save slice.call and call it as a plain function, because the call() method also reads its this value, which is the function it should call. In this case, you can use {{jsxref("Function/bind", "bind()")}} to bind the value of this for call(). In the following piece of code, slice() is a bound version of Function.prototype.call(), with the this value bound to {{jsxref("Array.prototype.slice()")}}. This means that additional call() calls can be eliminated

Attribution: Adapted from MDN Web Docs under CC-BY-SA-2.5. Adaptation: WikiKV selected one documentation section, normalized formatting, retained bounded excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.