About stdlib...
We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.
The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.
When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.
To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
Invoke a function for each own and inherited enumerable property of an object.
npm install @stdlib/utils-for-in
var forIn = require( '@stdlib/utils-for-in' );
Invokes a function
for each own and inherited enumerable property of an object
.
function log( value, key ) {
console.log( '%s: %d', key, value );
}
function Foo() {
this.a = 1;
this.b = 2;
return this;
}
Foo.prototype.c = 3;
Foo.prototype.d = 4;
var obj = new Foo();
forIn( 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
.
function log( value, key ) {
console.log( '%s: %d', key, value );
return false;
}
var obj = {
'a': 1,
'b': 2,
'c': 3,
'd': 4
};
forIn( obj, log );
// e.g., => a: 1
To set the function execution context, provide a thisArg
.
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
};
forIn( obj, sum, context );
var mean = context.sum / context.count;
// returns 2.5
- The function returns the input
object
. - Property iteration order is not guaranteed.
var fromCodePoint = require( '@stdlib/string-from-code-point' );
var forIn = require( '@stdlib/utils-for-in' );
function update( value, key, obj ) {
console.log( '%s: %d', key, value );
obj[ key ] *= value;
}
function Foo() {
return this;
}
Foo.prototype.beep = 3.14;
var obj;
var key;
var i;
obj = new Foo();
for ( i = 0; i < 26; i++ ) {
key = fromCodePoint( 97 + i );
obj[ key ] = i;
}
forIn( obj, update );
console.log( obj );
-
@stdlib/utils-for-each
: invoke a function for each element in a collection. -
@stdlib/utils-for-own
: invoke a function for each own enumerable property of an object.
This package is part of 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, see the main project repository.
See LICENSE.
Copyright © 2016-2024. The Stdlib Authors.