Invoke a function for each own enumerable property of an object.
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> Invoke a function for each own enumerable property of an object.
``bash`
npm install @stdlib/object-for-own
`javascript`
var forOwn = require( '@stdlib/object-for-own' );
#### forOwn( obj, fcn\[, thisArg ] )
Invokes a function for each own enumerable property of an object.
`javascript
function log( value, key ) {
console.log( '%s: %d', key, value );
}
var obj = {
'a': 1,
'b': 2,
'c': 3,
'd': 4
};
forOwn( obj, log );
/* e.g., =>
a: 1
b: 2
c: 3
d: 4
*/
`
The invoked function is provided three arguments:
- value: object property value.
- key: object property.
- obj: the input object.
To terminate iteration before visiting all properties, the provided function must explicitly return false.
`javascript
function log( value, key ) {
console.log( '%s: %d', key, value );
return false;
}
var obj = {
'a': 1,
'b': 2,
'c': 3,
'd': 4
};
forOwn( obj, log );
// e.g., => a: 1
`
To set the function execution context, provide a thisArg.
`javascript
function sum( value ) {
this.sum += value;
this.count += 1;
}
var obj = {
'a': 1,
'b': 2,
'c': 3,
'd': 4
};
var context = {
'sum': 0,
'count': 0
};
forOwn( obj, sum, context );
var mean = context.sum / context.count;
// returns 2.5
`
- The function returns the input object.object
- The function determines the list of own enumerable properties before invoking the provided function. Hence, any modifications made to the input after calling this function (such as adding and removing properties) will not affect the list of visited properties.
- Property iteration order is not guaranteed.
`javascript
var fromCodePoint = require( '@stdlib/string-from-code-point' );
var forOwn = require( '@stdlib/object-for-own' );
function update( value, key, obj ) {
console.log( '%s: %d', key, value );
obj[ key ] *= value;
}
var obj;
var key;
var i;
obj = {};
for ( i = 0; i < 26; i++ ) {
key = fromCodePoint( 97 + i );
obj[ key ] = i;
}
forOwn( obj, update );
console.log( obj );
`
*
- [@stdlib/utils-for-each][@stdlib/utils/for-each]: invoke a function for each element in a collection.
- [@stdlib/object-for-in][@stdlib/object/for-in]: invoke a function for each own and inherited enumerable property of an object.
*
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]
---
See [LICENSE][stdlib-license].
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
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[umd]: https://github.com/umdjs/umd
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[deno-url]: https://github.com/stdlib-js/object-for-own/tree/deno
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[umd-url]: https://github.com/stdlib-js/object-for-own/tree/umd
[umd-readme]: https://github.com/stdlib-js/object-for-own/blob/umd/README.md
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[@stdlib/utils/for-each]: https://www.npmjs.com/package/@stdlib/utils-for-each
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