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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!

anyByRight

NPM version Build Status Coverage Status

Test whether at least one element in a collection passes a test implemented by a predicate function, iterating from right to left.

Usage

To use in Observable,

anyByRight = require( 'https://cdn.jsdelivr.net/gh/stdlib-js/utils-any-by-right@umd/browser.js' )

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

var anyByRight = require( 'path/to/vendor/umd/utils-any-by-right/index.js' )

To include the bundle in a webpage,

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

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

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

anyByRight( collection, predicate[, thisArg ] )

Tests whether at least one element in a collection passes a test implemented by a predicate function, iterating from right to left.

function isNegative( value ) {
    return ( value < 0 );
}

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

var bool = anyByRight( arr, isNegative );
// returns true

If a predicate function returns a truthy value, the function immediately returns true.

function isNegative( value ) {
    if ( value > 0 ) {
        throw new Error( 'should never reach this line' );
    }
    return ( value < 0 );
}

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

var bool = anyByRight( arr, isNegative );
// returns true

The invoked function is provided three arguments:

  • value: collection element.
  • index: collection index.
  • collection: input collection.

To set the function execution context, provide a thisArg.

function sum( value ) {
    this.sum += value;
    this.count += 1;
    return ( value < 0 );
}

var arr = [ -5, 1, 2, 3, 4 ];

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

var bool = anyByRight( arr, sum, context );
// returns true

var mean = context.sum / context.count;
// returns 1.0

Notes

  • A collection may be either an Array, Typed Array, or an array-like Object (excluding strings and functions).

  • If provided an empty collection, the function returns false.

    function alwaysTrue() {
    return true;
}
var bool = anyByRight( [], alwaysTrue );
// returns false

  • The function differs from Array.prototype.some in the following ways:

    • The function does not skip undefined elements.

      function log( value, index ) {
    console.log( '%s: %s', index, value );
    return ( value < 0 );
}

var arr = [ -1, 1, , , 4 ];

var bool = anyByRight( arr, log );
/* =>
    4: 4
    3: undefined
    2: undefined
    1: 1
    0: -1
*/

    • The function provides limited support for dynamic collections (i.e., collections whose length changes during execution). Note, however, that index incrementation is not guaranteed to be monotonically decreasing.

Examples

<!DOCTYPE html>
<html lang="en">
<body>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/random-base-randu@umd/browser.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/utils-any-by-right@umd/browser.js"></script>
<script type="text/javascript">
(function () {

function threshold( value ) {
    return ( value > 0.95 );
}

var bool;
var arr;
var i;

arr = new Array( 100 );
for ( i = 0; i < arr.length; i++ ) {
    arr[ i ] = randu();
}

bool = anyByRight( arr, threshold );
// returns <boolean>

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

See Also

  • @stdlib/utils-any-by: test whether at least one element in a collection passes a test implemented by a predicate function.
  • @stdlib/utils-async/any-by-right: test whether at least one element in a collection passes a test implemented by a predicate function, iterating from right to left.
  • @stdlib/utils-every-by-right: test whether all elements in a collection pass a test implemented by a predicate function, iterating from right to left.
  • @stdlib/utils-for-each-right: invoke a function for each element in a collection, iterating from right to left.
  • @stdlib/utils-none-by-right: test whether all elements in a collection fail a test implemented by a predicate function, iterating from right to left.
  • @stdlib/utils-some-by-right: test whether a collection contains at least n elements which pass a test implemented by a predicate function, iterating from right to left.

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.

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.