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    @stdlib/iter-shift
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    0.0.7 • Public • Published

    iterShift

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    Create an iterator which skips the first value of a provided iterator.

    Installation

    npm install @stdlib/iter-shift

    Usage

    var iterShift = require( '@stdlib/iter-shift' );

    iterShift( iterator[, clbk[, thisArg]] )

    Returns an iterator which skips the first value of a provided iterator.

    var array2iterator = require( '@stdlib/array-to-iterator' );
    
    var it = iterShift( array2iterator( [ 1, 2, 3, 4 ] ) );
    // returns <Object>
    
    var v = it.next().value;
    // returns 2
    
    v = it.next().value;
    // returns 3
    
    v = it.next().value;
    // returns 4
    
    var bool = it.next().done;
    // returns true

    The returned iterator protocol-compliant object has the following properties:

    • next: function which returns an iterator protocol-compliant object containing the next iterated value (if one exists) assigned to a value property and a done property having a boolean value indicating whether the iterator is finished.
    • return: function which closes an iterator and returns a single (optional) argument in an iterator protocol-compliant object.

    To invoke a callback upon skipping the first value of a provided iterator, provide a clbk argument.

    var array2iterator = require( '@stdlib/array-to-iterator' );
    
    function onShift( v ) {
        console.log( v );
        // => 1
    }
    
    var it = iterShift( array2iterator( [ 1, 2, 3, 4 ] ), onShift );
    // returns <Object>
    
    var v = it.next().value;
    // returns 2
    
    v = it.next().value;
    // returns 3
    
    v = it.next().value;
    // returns 4
    
    var bool = it.next().done;
    // returns true

    The callback function is provided a single argument:

    • v: the skipped value

    To set the callback execution context, provide a thisArg.

    var array2iterator = require( '@stdlib/array-to-iterator' );
    
    function onShift() {
        this.count += 1;
    }
    
    var ctx = {
        'count': 0
    };
    
    var it = iterShift( array2iterator( [ 1, 2, 3, 4 ] ), onShift, ctx );
    // returns <Object>
    
    var v = it.next().value;
    // returns 2
    
    v = it.next().value;
    // returns 3
    
    v = it.next().value;
    // returns 4
    
    var bool = it.next().done;
    // returns true
    
    bool = ( ctx.count === 1 );
    // returns true

    Notes

    • If an environment supports Symbol.iterator and a provided iterator is iterable, the returned iterator is iterable.

    Examples

    var randu = require( '@stdlib/random-iter-randu' );
    var iterShift = require( '@stdlib/iter-shift' );
    
    // Create a seeded iterator for generating pseudorandom numbers:
    var rand = randu({
        'seed': 1234,
        'iter': 10
    });
    
    // Create an iterator which skips the first number:
    var it = iterShift( rand );
    
    // Perform manual iteration...
    var v;
    while ( true ) {
        v = it.next();
        if ( v.done ) {
            break;
        }
        console.log( v.value );
    }

    See Also

    • @stdlib/iter/pop: create an iterator which skips the last value of a provided iterator.
    • @stdlib/iter/slice: create an iterator which returns a subsequence of iterated values from a provided iterator.
    • @stdlib/iter/unshift: create an iterator which prepends values to the beginning of a provided iterator.

    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 © 2016-2022. The Stdlib Authors.

    Install

    npm i @stdlib/iter-shift

    Homepage

    stdlib.io

    DownloadsWeekly Downloads

    39

    Version

    0.0.7

    License

    Apache-2.0

    Unpacked Size

    45.1 kB

    Total Files

    9

    Last publish

    Collaborators

    • stdlib-bot
    • kgryte
    • planeshifter
    • rreusser