https://github.com/stdlib-js/array-base-index-of-same-value
Return the index of the first element which equals a provided search element according to the same value algorithm.
https://github.com/stdlib-js/array-base-index-of-same-value
array data find generic index javascript locate node node-js nodejs same scan search stdlib structure types
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Return the index of the first element which equals a provided search element according to the same value algorithm.
- Host: GitHub
- URL: https://github.com/stdlib-js/array-base-index-of-same-value
- Owner: stdlib-js
- License: apache-2.0
- Created: 2025-03-31T01:17:04.000Z (10 months ago)
- Default Branch: main
- Last Pushed: 2025-08-11T01:55:55.000Z (5 months ago)
- Last Synced: 2025-09-05T13:02:21.704Z (4 months ago)
- Topics: array, data, find, generic, index, javascript, locate, node, node-js, nodejs, same, scan, search, stdlib, structure, types
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 751 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
- Notice: NOTICE
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README
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# indexOfSameValue
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Return the index of the first element which equals a provided search element according to the [SameValue Algorithm][@stdlib/assert/is-same-value].
## Installation
```bash
npm install @stdlib/array-base-index-of-same-value
```
Alternatively,
- To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).
The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
## Usage
```javascript
var indexOfSameValue = require( '@stdlib/array-base-index-of-same-value' );
```
#### indexOfSameValue( x, searchElement, fromIndex )
Returns the index of the first element which equals a provided search element according to the [SameValue Algorithm][@stdlib/assert/is-same-value].
```javascript
var x = [ 1, 2, 3, 4, 5, 6 ];
var idx = indexOfSameValue( x, 3, 0 );
// returns 2
```
If the function is unable to find an element which equals a provided search element, the function returns `-1`.
```javascript
var x = [ 1, 2, 3, 4, 5, 6 ];
var idx = indexOfSameValue( x, 7, 0 );
// returns -1
```
To begin searching from specific index, provide a non-zero `fromIndex` argument.
```javascript
var x = [ 1, 1, 2, 1, 2, 3, 3 ];
var idx = indexOfSameValue( x, 2, 3 );
// returns 4
```
If `fromIndex` is less than zero, the starting index is resolved relative to the last array element, with the last array element corresponding to `fromIndex = -1`.
```javascript
var x = [ 1, 1, 2, 1, 2, 3, 3 ];
var idx = indexOfSameValue( x, 2, -4 );
// returns 4
```
## Notes
- The function performs a linear scan and returns immediately upon finding a match.
- When searching for a search element, the function checks for equality using the [SameValue Algorithm][@stdlib/assert/is-same-value] as specified in ECMAScript 5. As a consequence, `NaN` values are considered equal, and `-0` and `+0` are considered distinct.
## Examples
```javascript
var indexOfSameValue = require( '@stdlib/array-base-index-of-same-value' );
var x = [ 'foo', 'bar', 'beep', 'boop', 'foo', 'bar' ];
var idx = indexOfSameValue( x, 'beep', 0 );
// returns 2
idx = indexOfSameValue( x, 'bop', 0 );
// returns -1
idx = indexOfSameValue( x, 'foo', 1 );
// returns 4
idx = indexOfSameValue( x, 'foo', -4 );
// returns 4
idx = indexOfSameValue( x, 'foo', 5 );
// returns -1
```
* * *
## Notice
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
#### Community
[![Chat][chat-image]][chat-url]
---
## License
See [LICENSE][stdlib-license].
## Copyright
Copyright © 2016-2025. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/array-base-index-of-same-value.svg
[npm-url]: https://npmjs.org/package/@stdlib/array-base-index-of-same-value
[test-image]: https://github.com/stdlib-js/array-base-index-of-same-value/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/array-base-index-of-same-value/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/array-base-index-of-same-value/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/array-base-index-of-same-value?branch=main
[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/array-base-index-of-same-value/tree/deno
[deno-readme]: https://github.com/stdlib-js/array-base-index-of-same-value/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/array-base-index-of-same-value/tree/umd
[umd-readme]: https://github.com/stdlib-js/array-base-index-of-same-value/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/array-base-index-of-same-value/tree/esm
[esm-readme]: https://github.com/stdlib-js/array-base-index-of-same-value/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/array-base-index-of-same-value/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/array-base-index-of-same-value/main/LICENSE
[@stdlib/assert/is-same-value]: https://github.com/stdlib-js/assert-is-same-value