68 lines
1.5 KiB
JavaScript
68 lines
1.5 KiB
JavaScript
|
/**
|
||
|
|
* @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 isNonNegativeInteger = require( '@stdlib/assert/is-nonnegative-integer' ).isPrimitive;
|
||
|
|
|
||
|
|
|
||
|
|
// MAIN //
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns a function which always returns a specified argument.
|
||
|
|
*
|
||
|
|
* @param {NonNegativeInteger} idx - argument index
|
||
|
|
* @throws {TypeError} must provide a nonnegative integer
|
||
|
|
* @returns {Function} argument function
|
||
|
|
*
|
||
|
|
* @example
|
||
|
|
* var argn = wrap( 1 );
|
||
|
|
*
|
||
|
|
* var v = argn( 1.0, 2.0, 3.0 );
|
||
|
|
* // returns 2.0
|
||
|
|
*
|
||
|
|
* v = argn( 'a', 'b', 'c' );
|
||
|
|
* // returns 'b'
|
||
|
|
*
|
||
|
|
* v = argn( null );
|
||
|
|
* // returns undefined
|
||
|
|
*/
|
||
|
|
function wrap( idx ) {
|
||
|
|
if ( !isNonNegativeInteger( idx ) ) {
|
||
|
|
throw new TypeError( 'invalid argument. Must provide a nonnegative integer. Value: `'+idx+'`.' );
|
||
|
|
}
|
||
|
|
return argn;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Argument function.
|
||
|
|
*
|
||
|
|
* @private
|
||
|
|
* @returns {*} argument
|
||
|
|
*/
|
||
|
|
function argn() {
|
||
|
|
return arguments[ idx ];
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
// EXPORTS //
|
||
|
|
|
||
|
|
module.exports = wrap;
|