filterArguments

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

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 ) );
}