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    @stdlib/utils-none-by
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    0.0.7 • Public • Published

    noneBy

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    Test whether all elements in a collection fail a test implemented by a predicate function.

    Installation

    npm install @stdlib/utils-none-by

    Usage

    var noneBy = require( '@stdlib/utils-none-by' );

    noneBy( collection, predicate[, thisArg ] )

    Tests whether all elements in a collection fail a test implemented by a predicate function.

    function isPositive( value ) {
        return ( value > 0 );
    }
    
    var arr = [ -1, -2, -3, -4 ];
    
    var bool = noneBy( arr, isPositive );
    // returns true

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

    function isPositive( value ) {
        return ( value > 0 );
    }
    
    var arr = [ -1, 2, -3, -4 ];
    
    var bool = noneBy( arr, isPositive );
    // returns false

    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 ) {
        if ( value < 0 ) {
            return true;
        }
        this.sum += value;
        this.count += 1;
        return false;
    }
    
    var arr = [ 1, 2, 3, 4 ];
    
    var context = {
        'sum': 0,
        'count': 0
    };
    
    var bool = noneBy( arr, sum, context );
    // returns true
    
    var mean = context.sum / context.count;
    // returns 2.5

    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 true.

      function truthy() {
          return true;
      }
      var bool = noneBy( [], truthy );
      // returns true
    • The function does not skip undefined elements.

      function log( value, index ) {
          console.log( '%s: %s', index, value );
          return false;
      }
      
      var arr = [ 1, , , 4 ];
      
      var bool = noneBy( arr, log );
      /* =>
          0: 1
          1: undefined
          2: undefined
          3: 4
      */
    • The function provides limited support for dynamic collections (i.e., collections whose length changes during execution).

    Examples

    var randu = require( '@stdlib/random-base-randu' );
    var noneBy = require( '@stdlib/utils-none-by' );
    
    function isNegative( value ) {
        return ( value < 0 );
    }
    
    var bool;
    var arr;
    var i;
    
    arr = new Array( 100 );
    for ( i = 0; i < arr.length; i++ ) {
        arr[ i ] = randu();
    }
    
    bool = noneBy( arr, isNegative );
    // returns true

    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 © 2016-2021. The Stdlib Authors.

    Install

    npm i @stdlib/utils-none-by

    Homepage

    stdlib.io

    DownloadsWeekly Downloads

    6

    Version

    0.0.7

    License

    Apache-2.0

    Unpacked Size

    41.9 kB

    Total Files

    9

    Last publish

    Collaborators

    • stdlib-bot
    • kgryte
    • planeshifter
    • rreusser