@stdlib/utils/every-own-by/README.md

Standard utilities.

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# everyOwnBy

> Test whether all own propertes of an object pass a test implemented by a predicate function.

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## Usage

```javascript
var everyOwnBy = require( '@stdlib/utils/every-own-by' );
```

#### everyOwnBy( object, predicate\[, thisArg ] )

Tests whether all `own` properties of an object pass a test implemented by a `predicate` function.

```javascript
function isPositive( value ) {
    return ( value > 0 );
}

var obj = {
    'a': 1,
    'b': 2,
    'c': 3,
    'd': 4
};

var bool = everyOwnBy( obj, isPositive );
// returns true
```

If a `predicate` function returns a non-truthy value, the function **immediately** returns `false`.

```javascript
function isPositive( value ) {
    return ( value > 0 );
}

var obj = {
    'a': 1,
    'b': -2,
    'c': 3,
    'd': 4
};

var bool = everyOwnBy( obj, isPositive );
// returns false
```

The invoked `function` is provided three arguments:

-   **value**: property value.
-   **key**: property key.
-   **obj**: input object.

To set the function execution context, provide a `thisArg`.

```javascript
function sum( value ) {
    if ( value < 0 ) {
        return false;
    }
    this.sum += value;
    this.count += 1;
    return true;
}

var obj = {
    'a': 1,
    'b': 2,
    'c': 3
};

var context = {
    'sum': 0,
    'count': 0
};

var bool = everyOwnBy( obj, sum, context );
// returns true

var mean = context.sum / context.count;
// returns 2
```

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## Notes

-   If the 1st argument is not an [`object`][mdn-object] or the second argument is not a fuction , the
    function throws a Type Error.

-   If provided an empty object, the function returns `true`.

    ```javascript
    function untrue() {
        return false;
    }
    var bool = everyOwnBy( {}, untrue );
    // returns true
    ```

</section>

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## Examples

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

```javascript
var randu = require( '@stdlib/random/base/randu' );
var everyOwnBy = require( '@stdlib/utils/every-own-by' );

function isPositive( value ) {
    return ( value > 0 );
}

var obj = {};
var i;

// Populate object with random values
for ( i = 0; i < 100; i++ ) {
    obj[ 'prop_' + i ] = randu();
}

var bool = everyOwnBy( obj, isPositive );
// returns <boolean>
```

</section>

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* * *

## See Also

-   <span class="package-name">[`@stdlib/utils/any-own-by`][@stdlib/utils/any-own-by]</span><span class="delimiter">: </span><span class="description">test whether whether any 'own' property of a provided object satisfies a predicate function.</span>
-   <span class="package-name">[`@stdlib/utils/every-in-by`][@stdlib/utils/every-in-by]</span><span class="delimiter">: </span><span class="description">test whether all properties (own and inherited) of an object pass a test implemented by a predicate function.</span>
-   <span class="package-name">[`@stdlib/utils/none-own-by`][@stdlib/utils/none-own-by]</span><span class="delimiter">: </span><span class="description">tests whether every own property of an object fails a test implemented by a predicate function.</span>
-   <span class="package-name">[`@stdlib/utils/some-own-by`][@stdlib/utils/some-own-by]</span><span class="delimiter">: </span><span class="description">test whether some `own` properties of a provided object satisfy a predicate function for at least `n` properties.</span>
-   <span class="package-name">[`@stdlib/utils/every-by`][@stdlib/utils/every-by]</span><span class="delimiter">: </span><span class="description">test whether all elements in a collection pass a test implemented by a predicate function.</span>

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[mdn-object]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object

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[@stdlib/utils/any-own-by]: https://github.com/stdlib-js/utils/tree/main/any-own-by

[@stdlib/utils/every-in-by]: https://github.com/stdlib-js/utils/tree/main/every-in-by

[@stdlib/utils/none-own-by]: https://github.com/stdlib-js/utils/tree/main/none-own-by

[@stdlib/utils/some-own-by]: https://github.com/stdlib-js/utils/tree/main/some-own-by

[@stdlib/utils/every-by]: https://github.com/stdlib-js/utils/tree/main/every-by

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