npm package: @stdlib/assert-is-circular
Description: Test if an object-like value contains a circular reference.
Author: The Stdlib Authors
Latest version: 0.2.3

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<details>
  <summary>
    About stdlib...
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# isCircular

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> Test if an object-like value contains a circular reference.

<section class="installation">

## Installation

```bash
npm install @stdlib/assert-is-circular
```

</section>

<section class="usage">

## Usage

```javascript
var isCircular = require( '@stdlib/assert-is-circular' );
```

#### isCircular( value )

Tests if an object-like `value` contains a circular reference.

```javascript
var obj = {
    'beep': 'boop'
};
var bool = isCircular( obj );
// returns false

obj.self = obj;
bool = isCircular( obj );
// returns true
```

</section>

<!-- /.usage -->

<!-- /.usage -->

<section class="notes">

## Notes

-   Object-like values include `objects` (except for `null`), `arrays`, `functions`, regular expressions, `Date` objects, and any other JavaScript object to which properties may be bound.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

<!-- eslint-disable no-empty-function -->

<!-- eslint no-undef: "error" -->

```javascript
var isCircular = require( '@stdlib/assert-is-circular' );

var obj1 = {
    'a': 'beep',
    'b': {
        'c': 'boop'
    }
};
obj1.b.self = obj1;
var bool = isCircular( obj1 );
// returns true

var obj2 = {
    'a': {},
    'b': obj1
};
bool = isCircular( obj2 );
// returns true

var arr = [ 1, 2, 3 ];
arr.push( arr );
bool = isCircular( arr );
// returns true

function circ() {}
circ.self = circ;
bool = isCircular( circ );
// returns true

var obj3 = {
    'beep': 'boop'
};
bool = isCircular({
    'a': obj3,
    'b': obj3
});
// returns false

bool = isCircular( {} );
// returns false

bool = isCircular( null );
// returns false
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/assert-is-circular-array`][@stdlib/assert/is-circular-array]</span><span class="delimiter">: </span><span class="description">test if a value is an array containing a circular reference.</span>
-   <span class="package-name">[`@stdlib/assert-is-circular-plain-object`][@stdlib/assert/is-circular-plain-object]</span><span class="delimiter">: </span><span class="description">test if a value is a plain object containing a circular reference.</span>

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->


<section class="main-repo" >

* * *

## 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 &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

</section>

<!-- /.stdlib -->

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[npm-image]: http://img.shields.io/npm/v/@stdlib/assert-is-circular.svg
[npm-url]: https://npmjs.org/package/@stdlib/assert-is-circular

[test-image]: https://github.com/stdlib-js/assert-is-circular/actions/workflows/test.yml/badge.svg?branch=v0.2.3
[test-url]: https://github.com/stdlib-js/assert-is-circular/actions/workflows/test.yml?query=branch:v0.2.3

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/assert-is-circular/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/assert-is-circular?branch=main

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[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/assert-is-circular/tree/deno
[deno-readme]: https://github.com/stdlib-js/assert-is-circular/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/assert-is-circular/tree/umd
[umd-readme]: https://github.com/stdlib-js/assert-is-circular/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/assert-is-circular/tree/esm
[esm-readme]: https://github.com/stdlib-js/assert-is-circular/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/assert-is-circular/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/assert-is-circular/main/LICENSE

<!-- <related-links> -->

[@stdlib/assert/is-circular-array]: https://www.npmjs.com/package/@stdlib/assert-is-circular-array

[@stdlib/assert/is-circular-plain-object]: https://www.npmjs.com/package/@stdlib/assert-is-circular-plain-object

<!-- </related-links> -->

</section>

<!-- /.links -->