filterArguments

Create a function that invokes a provided function according to a predicate function.

Installation

npm install @stdlib/utils-filter-arguments

Usage

var filterArguments = require( '@stdlib/utils-filter-arguments' );

filterArguments( fcn, predicate[, thisArg] )

Returns a function that invokes a provided function according to a predicate function.

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

function predicate( v ) {
    return ( v !== 2 );
}

var bar = filterArguments( foo, predicate );

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

The predicate function is provided the following arguments:

• value: argument value.
• index: argument index.

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

function predicate( v ) {
    return ( v !== 2 );
}

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 = filterArguments( foo.scale, predicate, ctx );

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

Notes

• Only those arguments in which the predicate function returns a truthy value are applied to a provided function.

Examples

var filledarrayBy = require( '@stdlib/array-filled-by' );
var add = require( '@stdlib/math-base-ops-add' );
var filterArguments = require( '@stdlib/utils-filter-arguments' );

function fill( i ) {
    return i;
}

function factory( i, j ) {
    return predicate;

    function predicate( value, index ) {
        return ( i <= index ) && ( index < j );
    }
}

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

// Compute the sum of consecutive elements...
var f;
var i;
for ( i = 0; i < x.length-1; i++ ) {
    f = filterArguments( add, factory( i, i+2 ) );
    console.log( 'sum(x_%d, x_%d) = %d', i, i+1, f.apply( null, x ) );
}

See Also

• @stdlib/utils-mask-arguments: create a function that invokes a provided function according to an argument mask.
• @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.

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.