@stdlib/assert/deep-has-own-property/README.md

Standard assertion utilities.

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# deepHasOwnProp

> Test whether an object contains a nested key path.

<section class="usage">

## Usage

```javascript
var deepHasOwnProp = require( '@stdlib/assert/deep-has-own-property' );
```

#### deepHasOwnProp( value, path\[, options] )

Returns a `boolean` indicating if a `value` has a specified `path`.

<!-- eslint-disable object-curly-newline, object-curly-spacing -->

```javascript
var obj = { 'a': { 'b': { 'c': 'd' } } };

var bool = deepHasOwnProp( obj, 'a.b.c' );
// returns true

bool = deepHasOwnProp( obj, 'a.b.c.d.e' );
// returns false
```

If a key path includes an `array`, specify the numeric index.

<!-- eslint-disable object-curly-newline, object-curly-spacing -->

```javascript
var arr = [
    {
        'a': [
            {
                'b': [
                    { 'c': 'd' },
                    { 'e': 'f' }
                ]
            }
        ]
    }
];

var bool = deepHasOwnProp( arr, '0.a.0.b.0.c' );
// returns true

bool = deepHasOwnProp( arr, '0.a.1.b.0.c' );
// returns false

bool = deepHasOwnProp( arr, '0.a.0.b.1.c' );
// returns false
```

The key path may be specified as either a delimited `string` or a key `array`.

<!-- eslint-disable object-curly-newline, object-curly-spacing -->

```javascript
var obj = { 'a': { 'b': { 'c': 'd' } } };

var bool = deepHasOwnProp( obj, [ 'a', 'b', 'c' ] );
// returns true
```

The function accepts the following `options`:

-   **sep**: key path separator. Default: `'.'`.

By default, the function assumes `.` separated key values. To specify an alternative separator, set the `sep` option.

<!-- eslint-disable object-curly-newline, object-curly-spacing -->

```javascript
var obj = { 'a': { 'b': { 'c': 'd' } } };

var bool = deepHasOwnProp( obj, 'a/b/c', {
    'sep': '/'
});
// returns true
```

#### deepHasOwnProp.factory( path\[, options] )

Returns a `function` which tests whether a `value` contains a nested key `path`.

```javascript
var has = deepHasOwnProp.factory( 'a/b/c', {
    'sep': '/'
});
```

#### has( value )

Returns a `boolean` indicating whether a `value` contains a nested key `path`.

<!-- eslint-disable object-curly-newline, object-curly-spacing -->

```javascript
var has = deepHasOwnProp.factory( 'a.b.c' );

var obj = { 'a': { 'b': { 'c': 'd' } } };

var bool = has( obj );
// returns true
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   Only **own** properties are tested. Paths matching inherited properties are not considered.

    ```javascript
    function Foo() {
        this.a = 'b';
        return this;
    }
    Foo.prototype.c = 'd';

    var foo = new Foo();

    var bool = deepHasOwnProp( foo, 'a' );
    // returns true

    bool = deepHasOwnProp( foo, 'c' );
    // returns false
    ```

-   When provided `null` or `undefined`, the function result is always `false`.

    ```javascript
    var bool = deepHasOwnProp( null, 'a.b.c' );
    // returns false

    bool = deepHasOwnProp( void 0, 'a.b.c' );
    // returns false
    ```

-   Property values other than `null` or `undefined` are coerced to `objects`.

    ```javascript
    var obj = {
        'a': 'b'
    };

    var bool = deepHasOwnProp( obj, 'a.length' );
    // returns true
    ```

-   Key path `array` elements are coerced to `strings`.

    ```javascript
    var obj = {
        'null': false
    };
    var bool = deepHasOwnProp( obj, [ null ] );
    // returns true

    obj = {
        '[object Object]': false
    };
    bool = deepHasOwnProp( obj, [ {} ] );
    // returns true
    ```

</section>

<!-- /.notes -->

<section class="examples">

## Examples

<!-- eslint-disable object-curly-newline, object-curly-spacing -->

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

```javascript
var deepHasOwnProp = require( '@stdlib/assert/deep-has-own-property' );

var bool = deepHasOwnProp( { 'a': { 'b': { 'c': 'd' } } }, 'a.b.c' );
// returns true

bool = deepHasOwnProp( { 'a': { 'b': { 'c': 'd' } } }, [ 'a', 'b', 'c' ] );
// returns true

bool = deepHasOwnProp( { 'a': { 'b': { 'c': 'd' } } }, 'a/b/c', {
    'sep': '/'
});
// returns true

bool = deepHasOwnProp( { 'a': { 'b': { 'c': 'd' } } }, 'a.b.c.d' );
// returns false

bool = deepHasOwnProp( { 'a': [ { 'b': { 'c': 'd' } } ] }, [ 'a', '0', 'b', 'c', 'd' ] );
// returns false

bool = deepHasOwnProp( { 'a': { 'b': { 'c': 'd' } } }, 'a/b/c/d/e', {
    'sep': '/'
});
// returns false

// Create a customized function:
var has = deepHasOwnProp.factory( 'a_b_c', {
    'sep': '_'
});

bool = has( { 'a': { 'b': { 'c': 'd' } } } );
// returns true

bool = has( { 'a': [ { 'b': { 'c': 'd' } } ] } );
// 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/deep-has-property`][@stdlib/assert/deep-has-property]</span><span class="delimiter">: </span><span class="description">test whether an object contains a nested key path, either own or inherited.</span>
-   <span class="package-name">[`@stdlib/assert/has-own-property`][@stdlib/assert/has-own-property]</span><span class="delimiter">: </span><span class="description">test if an object has a specified property.</span>
-   <span class="package-name">[`@stdlib/utils/deep-get`][@stdlib/utils/deep-get]</span><span class="delimiter">: </span><span class="description">get a nested property value.</span>
-   <span class="package-name">[`@stdlib/utils/deep-pluck`][@stdlib/utils/deep-pluck]</span><span class="delimiter">: </span><span class="description">extract a nested property value from each element of an object array.</span>
-   <span class="package-name">[`@stdlib/utils/deep-set`][@stdlib/utils/deep-set]</span><span class="delimiter">: </span><span class="description">set a nested property value.</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/deep-has-property]: https://github.com/stdlib-js/assert/tree/main/deep-has-property

[@stdlib/assert/has-own-property]: https://github.com/stdlib-js/assert/tree/main/has-own-property

[@stdlib/utils/deep-get]: https://www.npmjs.com/package/@stdlib/utils-deep-get

[@stdlib/utils/deep-pluck]: https://www.npmjs.com/package/@stdlib/utils-deep-pluck

[@stdlib/utils/deep-set]: https://www.npmjs.com/package/@stdlib/utils-deep-set

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

</section>

<!-- /.links -->