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maskArguments

Create a function that invokes a provided function according to an argument mask.

Installation

npm install @stdlib/utils-mask-arguments

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var maskArguments = require( '@stdlib/utils-mask-arguments' );

maskArguments( fcn, mask[, thisArg] )

Returns a function that invokes a provided function according to an argument mask.

function foo( a, b ) {
    return [ a, b ];
}

var bar = maskArguments( foo, [ 1, 0, 1 ] );

var out = bar( 1, 2, 3 );
// returns [ 1, 3 ]

To set the this context when invoking the provided function, provide a thisArg.

function Foo() {
    this.x = 1;
    this.y = 2;
}

Foo.prototype.scale = function scale( a, b ) {
    return [ this.x*a, this.y*b ];
};

var ctx = {
    'x': 10,
    'y': 20
};

var foo = new Foo();

var bar = maskArguments( foo.scale, [ 1, 0, 1 ], ctx );

var out = bar( 1, 2, 3 );
// returns [ 10, 60 ]

Notes

• Only those arguments having a truthy mask value are applied to a provided function.

Examples

var filledarrayBy = require( '@stdlib/array-filled-by' );
var Uint8Array = require( '@stdlib/array-uint8' );
var add = require( '@stdlib/math-base-ops-add' );
var maskArguments = require( '@stdlib/utils-mask-arguments' );

function fill( i ) {
    return i;
}

// Create a data array:
var x = filledarrayBy( 10, 'float64', fill );

// Create a mask array:
var mask = new Uint8Array( x.length );

// "Unmask" the first element:
mask[ 0 ] = 1;

// Compute the sum of consecutive elements...
var f;
var i;
for ( i = 1; i < x.length; i++ ) {
    // "Unmask" the next element:
    mask[ i ] = 1;

    // Compute the sum:
    f = maskArguments( add, mask );
    console.log( 'sum(x_%d, x_%d) = %d', i-1, i, f.apply( null, x ) );

    // Update the mask:
    mask[ i-1 ] = 0;
}

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See Also

• @stdlib/utils-filter-arguments: create a function that invokes a provided function according to a predicate function.
• @stdlib/utils-reject-arguments: create a function that invokes a provided function according to a predicate function.
• @stdlib/utils-reorder-arguments: create a function that invokes a provided function with reordered arguments.
• @stdlib/utils-reverse-arguments: create a function that invokes a provided function with arguments in reverse order.

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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

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.