AccessorArray

Create a minimal array-like object supporting the accessor protocol from another array-like object.

Installation

npm install @stdlib/array-base-accessor

Usage

var AccessorArray = require( '@stdlib/array-base-accessor' );

AccessorArray( arr )

Creates a minimal array-like object supporting the accessor protocol from another array-like object.

var arr = new AccessorArray( [ 1, 2, 3 ] );
// returns <AccessorArray>

Properties

AccessorArray.prototype.length

Number of array elements.

var arr = new AccessorArray( [ 1, 2, 3 ] );
// returns <AccessorArray>

var len = arr.length;
// returns 3

Methods

AccessorArray.prototype.get( i )

Returns an array element located at position (index) i.

var arr = new AccessorArray( [ 1, 2, 3 ] );

// Get the first element:
var v = arr.get( 0 );
// returns 1

AccessorArray.prototype.set( v[, i] )

Set an array element.

var arr = new AccessorArray( [ 1, 2, 3 ] );

// Get the first element:
var v = arr.get( 0 );
// returns 1

// Set the first element:
arr.set( 5 );

// Get the first element:
v = arr.get( 0 );
// returns 5

By default, the method sets array elements starting at position (index) i = 0. To set elements starting elsewhere in the array, provide an index argument i.

var arr = new AccessorArray( [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ] );

// Get the fifth element:
var v = arr.get( 4 );
// returns 5

// Set the fifth element:
arr.set( 11, 4 );

// Get the fifth element:
v = arr.get( 4 );
// returns 11

Examples

var AccessorArray = require( '@stdlib/array-base-accessor' );

// Define a class for creating a minimal sparse array-like object...
function SparseArray( len, values ) {
    this.length = len;
    this._data = values;
    return this;
}

SparseArray.prototype.get = function get( i ) {
    var v = this._data[ i ];
    if ( v === void 0 ) {
        return 0;
    }
    return v;
};

SparseArray.prototype.set = function set( v, i ) {
    this._data[ i ] = v;
};

// Define a function for printing the contents of an array and which assumes accessor protocol support:
function printArray( name, x ) {
    var i;
    for ( i = 0; i < x.length; i++ ) {
        console.log( '%s[%d] = %d', name, i, x.get( i ) );
    }
}

// Create a sparse array-like object:
var sparse = new SparseArray( 10, {
    '2': 1,
    '3': 2,
    '8': 3
});

// Create a dense array:
var arr = [ 0, 0, 1, 2, 0, 0, 0, 0, 3, 0 ];

// Convert the dense array to an accessor array to allow for uniform iteration:
var dense = new AccessorArray( arr );

// Print the contents of each array...
printArray( 'sparse', sparse );
printArray( 'dense', dense );

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

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.