All files / papply-right/lib main.js

59.34% Statements 54/91
100% Branches 1/1
0% Functions 0/1
59.34% Lines 54/91

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 921x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x                                                                           1x 1x 1x 1x 1x  
/**
* @license Apache-2.0
*
* Copyright (c) 2018 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*    http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
 
'use strict';
 
// MODULES //
 
var isFunction = require( '@stdlib/assert/is-function' );
var format = require( '@stdlib/string/format' );
 
 
// MAIN //
 
/**
* Returns a function of smaller arity by partially applying arguments from the right.
*
* @param {Function} fcn - function to partially apply
* @param {...*} [args] - arguments to partially apply
* @throws {TypeError} first argument must be a function
* @returns {Function} partially applied function
*
* @example
* function say( text, name ) {
*     return text + ', ' + name + '.';
* }
*
* var toGrace = papplyRight( say, 'Grace Hopper' );
*
* var str = toGrace( 'Hello' );
* // returns 'Hello, Grace Hopper.'
*
* str = toGrace( 'Thank you' );
* // returns 'Thank you, Grace Hopper.'
*/
function papplyRight( fcn ) {
	var pargs;
	var len;
	var i;
	if ( !isFunction( fcn ) ) {
		throw new TypeError( format( 'invalid argument. First argument must be a function. Value: `%s`.', fcn ) );
	}
	len = arguments.length - 1;
	pargs = new Array( len );
	for ( i = 1; i < arguments.length; i++ ) {
		pargs[ i-1 ] = arguments[ i ];
	}
	return pappliedRight;

	/**
	* Partially applied function.
	*
	* @private
	* @param {...*} [args] - function arguments
	* @returns {*} partially applied function result
	*/
	function pappliedRight() {
		var nargs;
		var args;
		var j;
		nargs = arguments.length;
		args = new Array( len+nargs );
		for ( j = 0; j < args.length; j++ ) {
			if ( j >= nargs ) {
				args[ j ] = pargs[ j-nargs ];
			} else {
				args[ j ] = arguments[ j ];
			}
		}
		return fcn.apply( null, args );
	}
}
 
 
// EXPORTS //
 
module.exports = papplyRight;