@stdlib/assert/is-circular/README.md

Standard assertion utilities.

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# isCircular

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

<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="links">

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

[@stdlib/assert/is-circular-array]: https://github.com/stdlib-js/assert/tree/main/is-circular-array

[@stdlib/assert/is-circular-plain-object]: https://github.com/stdlib-js/assert/tree/main/is-circular-plain-object

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

</section>

<!-- /.links -->