68 lines
1.9 KiB
JavaScript
68 lines
1.9 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 isFunction = require( '@stdlib/assert/is-function' );
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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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* Invokes a function `n` times and returns an array of accumulated function return values.
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*
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* @param {Function} fcn - function to invoke
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* @param {NonNegativeInteger} n - number of function invocations
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* @param {*} [thisArg] - execution context
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* @throws {TypeError} first argument must be a function
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* @throws {TypeError} second argument must be a nonnegative integer
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* @returns {Array} accumulated results
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*
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* @example
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* function fcn( i ) {
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* return i;
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* }
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*
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* var arr = mapFun( fcn, 5 );
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* // returns [ 0, 1, 2, 3, 4 ]
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*/
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function mapFun( fcn, n, thisArg ) {
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var out;
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var i;
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if ( !isFunction( fcn ) ) {
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throw new TypeError( 'invalid argument. First argument must be a function. Value: `'+fcn+'`.' );
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}
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if ( !isNonNegativeInteger( n ) ) {
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throw new TypeError( 'invalid argument. Second argument must be a nonnegative integer. Value: `'+n+'`.' );
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}
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// Note: we explicitly do not preallocate in order to ensure "fast" elements for large output arrays.
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out = [];
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for ( i = 0; i < n; i++ ) {
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out.push( fcn.call( thisArg, i ) );
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}
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return out;
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}
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// EXPORTS //
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module.exports = mapFun;
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