68 lines
1.5 KiB
JavaScript
68 lines
1.5 KiB
JavaScript
/**
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* @license Apache-2.0
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*
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* Copyright (c) 2018 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var isNonNegativeInteger = require( '@stdlib/assert/is-nonnegative-integer' ).isPrimitive;
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// MAIN //
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/**
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* Returns a function which always returns a specified argument.
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*
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* @param {NonNegativeInteger} idx - argument index
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* @throws {TypeError} must provide a nonnegative integer
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* @returns {Function} argument function
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*
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* @example
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* var argn = wrap( 1 );
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*
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* var v = argn( 1.0, 2.0, 3.0 );
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* // returns 2.0
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*
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* v = argn( 'a', 'b', 'c' );
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* // returns 'b'
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*
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* v = argn( null );
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* // returns undefined
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*/
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function wrap( idx ) {
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if ( !isNonNegativeInteger( idx ) ) {
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throw new TypeError( 'invalid argument. Must provide a nonnegative integer. Value: `'+idx+'`.' );
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}
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return argn;
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/**
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* Argument function.
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*
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* @private
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* @returns {*} argument
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*/
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function argn() {
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return arguments[ idx ];
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}
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}
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// EXPORTS //
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module.exports = wrap;
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