@stdlib/utils-push
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    0.0.6 • Public • Published

    push

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    Add one or more elements to the end of a collection.

    Installation

    npm install @stdlib/utils-push

    Usage

    var push = require( '@stdlib/utils-push' );

    push( collection, ...items )

    Adds one or more elements to the end of a collection. A collection may be either an Array, Typed Array, or an array-like Object (i.e., an Object having a valid writable length property).

    var arr = [ 1.0, 2.0, 3.0, 4.0, 5.0 ];
    
    var out = push( arr, 6.0, 7.0 );
    // returns [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0 ]
    
    var bool = ( out === arr );
    // returns true

    In contrast to Array.prototype.push, the function returns the extended collection, rather than the collection length. For typed arrays, the returned value is a new typed array view whose underlying ArrayBuffer may not equal the underlying ArrayBuffer for the input collection.

    var ArrayBuffer = require( '@stdlib/array-buffer' );
    var Float64Array= require( '@stdlib/array-float64' );
    
    var buf = new ArrayBuffer( 3*8 ); // 8 bytes per double
    
    var arr = new Float64Array( buf, 0, 2 );
    arr[ 0 ] = 1.0;
    arr[ 1 ] = 2.0;
    
    var out = push( arr, 3.0 );
    // returns <Float64Array>[ 1.0, 2.0, 3.0 ]
    
    var bool = ( out === arr );
    // returns false
    
    bool = ( out.buffer === arr.buffer );
    // returns true
    
    out = push( out, 4.0 );
    // returns <Float64Array>[ 1.0, 2.0, 3.0, 4.0 ]
    
    bool = ( out.buffer === arr.buffer );
    // returns false

    Notes

    • The function adds one or more elements to a typed array by setting values in the underlying ArrayBuffer. If an ArrayBuffer does not have enough bytes in which to store all elements, the function allocates a new ArrayBuffer capable of holding 2^n elements, where n is the next power of 2. This procedure is similar to how environments internally handle dynamic memory allocation for Arrays.
    • Beware when providing typed arrays which are views pointing to a shared (or pooled) ArrayBuffer. Because the function sets ArrayBuffer bytes outside of a provided view, the function may overwrite bytes belonging to one or more external views. This could be a potential security vulnerability. Prefer providing typed arrays which have an exclusive ArrayBuffer; otherwise, be sure to plan for and guard against mutated state.

    Examples

    var Float64Array= require( '@stdlib/array-float64' );
    var push = require( '@stdlib/utils-push' );
    
    var arr;
    var i;
    
    arr = new Float64Array();
    for ( i = 0; i < 100; i++ ) {
        arr = push( arr, i );
    }
    console.log( arr );

    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-push

    Homepage

    stdlib.io

    DownloadsWeekly Downloads

    5

    Version

    0.0.6

    License

    Apache-2.0

    Unpacked Size

    47 kB

    Total Files

    12

    Last publish

    Collaborators

    • stdlib-bot
    • kgryte
    • planeshifter
    • rreusser