86 lines
2.5 KiB
JavaScript
86 lines
2.5 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 isCollection = require( '@stdlib/assert/is-collection' );
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var isPositiveInteger = require( '@stdlib/assert/is-positive-integer' ).isPrimitive;
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var isFunction = require( '@stdlib/assert/is-function' );
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// MAIN //
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/**
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* Tests whether a collection contains at least `n` elements which pass a test implemented by a predicate function.
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*
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* @param {Collection} collection - input collection
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* @param {PositiveInteger} n - number of elements
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* @param {Function} predicate - test function
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* @param {*} [thisArg] - execution context
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* @throws {TypeError} first argument must be a collection
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* @throws {TypeError} second argument must be a positive integer
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* @throws {TypeError} third argument must be a function
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* @returns {boolean} boolean indicating whether a collection contains at least `n` elements which pass a test
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*
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* @example
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* function isNegative( v ) {
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* return ( v < 0 );
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* }
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*
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* var arr = [ 1, 2, -3, 4, -1 ];
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*
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* var bool = someBy( arr, 2, isNegative );
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* // returns true
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*/
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function someBy( collection, n, predicate, thisArg ) {
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var count;
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var out;
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var len;
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var i;
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if ( !isCollection( collection ) ) {
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throw new TypeError( 'invalid argument. First argument must be a collection. Value: `'+collection+'`.' );
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}
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if ( !isPositiveInteger( n ) ) {
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throw new TypeError( 'invalid argument. Second argument must be a positive integer. Value: `'+n+'`.' );
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}
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if ( !isFunction( predicate ) ) {
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throw new TypeError( 'invalid argument. Third argument must be a function. Value: `'+predicate+'`.' );
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}
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len = collection.length;
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count = 0;
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for ( i = 0; i < len; i++ ) {
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out = predicate.call( thisArg, collection[ i ], i, collection );
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if ( out ) {
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count += 1;
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if ( count === n ) {
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return true;
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}
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}
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// Account for dynamically resizing a collection:
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len = collection.length;
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}
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return false;
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}
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// EXPORTS //
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module.exports = someBy;
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