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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!

everyBy

NPM version Build Status Coverage Status

Test whether all elements in an array pass a test implemented by a predicate function.

Usage

To use in Observable,

everyBy = require( 'https://cdn.jsdelivr.net/gh/stdlib-js/array-base-every-by@umd/browser.js' )

To vendor stdlib functionality and avoid installing dependency trees for Node.js, you can use the UMD server build:

var everyBy = require( 'path/to/vendor/umd/array-base-every-by/index.js' )

To include the bundle in a webpage,

<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/array-base-every-by@umd/browser.js"></script>

If no recognized module system is present, access bundle contents via the global scope:

<script type="text/javascript">
(function () {
    window.everyBy;
})();
</script>

everyBy( x, predicate[, thisArg] )

Tests whether all elements in an array pass a test implemented by a predicate function.

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

var x = [ 1, 2, 3, 4 ];

var bool = everyBy( x, isPositive );
// returns true

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

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

var x = [ 1, -2, 3, 4 ];

var bool = everyBy( x, isPositive );
// returns false

The predicate function is provided three arguments:

  • value: current array element.
  • index: current array element index.
  • arr: input array.

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

function predicate( value ) {
    this.count += 1;
    return ( value > 0 );
}

var x = [ 1, 2, -3, 4 ];

var context = {
    'count': 0
};

var bool = everyBy( x, predicate, context );
// returns false

var cnt = context.count;
// returns 3

Notes

  • If provided an array-like object having an every method, the function defers execution to that method and assumes that the method API has the following signature:

    x.every( predicate, thisArg )

  • If provided an array-like object without an every method, the function performs a linear scan and returns immediately upon encountering a non-truthy return value. Unlike Array.prototype.every, when performing a linear scan, the function does not skip undefined elements.

  • If provided an empty array, the function returns true.

Examples

<!DOCTYPE html>
<html lang="en">
<body>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/random-array-discrete-uniform@umd/browser.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/assert-is-positive-integer@umd/browser.js"></script>
<script type="text/javascript">
(function () {.isPrimitive;
var naryFunction = require( '@stdlib/utils-nary-function' );
var everyBy = require( '@stdlib/array-base-every-by' );

var x = discreteUniform( 10, 0, 10, {
    'dtype': 'int32'
});
// returns <Int32Array>

var out = everyBy( x, naryFunction( isPositiveInteger, 1 ) );
// returns <boolean>

})();
</script>
</body>
</html>

Notice

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.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.