115 lines
3.3 KiB
JavaScript
115 lines
3.3 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 isFunction = require( '@stdlib/assert/is-function' );
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var validate = require( './validate.js' );
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var returnValues = require( './return_values.js' );
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var returnIndices = require( './return_indices.js' );
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var returnPairs = require( './return_pairs.js' );
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// MAIN //
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/**
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* Splits values into two groups according to a predicate function.
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*
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* @param {Collection} collection - input collection
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* @param {Options} [options] - function options
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* @param {*} [options.thisArg] - execution context
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* @param {string} [options.returns="values"] - if `values`, values are returned; if `indices`, indices are returned; if `*`, both indices and values are returned
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* @param {Function} predicate - predicate function indicating which group an element in the input collection belongs to
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* @throws {TypeError} first argument must be a collection
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* @throws {TypeError} options argument must be an object
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* @throws {TypeError} last argument must be a function
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* @throws {TypeError} must provide valid options
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* @returns {(Array<Array>|Array)} group results
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*
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* @example
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* function predicate( v ) {
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* return v[ 0 ] === 'b';
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* }
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* var arr = [ 'beep', 'boop', 'foo', 'bar' ];
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*
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* var out = bifurcateBy( arr, predicate );
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* // returns [ [ 'beep', 'boop', 'bar' ], [ 'foo' ] ]
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*
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* @example
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* function predicate( v ) {
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* return v[ 0 ] === 'b';
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* }
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* var arr = [ 'beep', 'boop', 'foo', 'bar' ];
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*
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* var opts = {
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* 'returns': 'indices'
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* };
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* var out = bifurcateBy( arr, opts, predicate );
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* // returns [ [ 0, 1, 3 ], [ 2 ] ]
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*
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* @example
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* function predicate( v ) {
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* return v[ 0 ] === 'b';
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* }
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* var arr = [ 'beep', 'boop', 'foo', 'bar' ];
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*
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* var opts = {
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* 'returns': '*'
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* };
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* var out = bifurcateBy( arr, opts, predicate );
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* // returns [ [ [ 0, 'beep' ], [ 1, 'boop' ], [ 3, 'bar' ] ], [ [ 2, 'foo' ] ] ]
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*/
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function bifurcateBy( collection, options, predicate ) {
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var opts;
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var err;
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var cb;
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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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opts = {
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'returns': 'values'
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};
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if ( arguments.length === 2 ) {
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cb = options;
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} else {
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err = validate( opts, options );
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if ( err ) {
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throw err;
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}
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cb = predicate;
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}
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if ( !isFunction( cb ) ) {
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throw new TypeError( 'invalid argument. Last argument must be a function. Value: `'+cb+'`.' );
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}
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if ( opts.returns === 'values' ) {
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return returnValues( collection, opts, cb );
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}
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if ( opts.returns === 'indices' ) {
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return returnIndices( collection, opts, cb );
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}
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return returnPairs( collection, opts, cb );
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}
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// EXPORTS //
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module.exports = bifurcateBy;
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