// wink-nlp-utils
// NLP Functions for amplifying negations, managing elisions,
// creating ngrams, stems, phonetic codes to tokens and more.
//
// Copyright (C) GRAYPE Systems Private Limited
//
// This file is part of “wink-nlp-utils”.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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// DEALINGS IN THE SOFTWARE.
//
// ## string
// ### returnWordsFilter
/**
*
* Returns an object containing the following functions: (a) `set()`, which returns
* a set of mapped words given in the input array `words`. (b) `exclude()` that
* is suitable for array filtering operations.
*
* If the second argument `mappers` is provided as an array of maping functions
* then these are applied on the input array before converting into a set. A
* mapper function must accept a string as argument and return a string as the result.
* Examples of mapper functions are typically **string** functionss of **`wink-nlp-utils`**
* such as `string.lowerCase()`, `string.stem()` and
* `string.soundex()`.
*
* @alias helper#returnWordsFilter
* @param {string[]} words that can be filtered using the returned wordsFilter.
* @param {function[]} [mappers=undefined] optionally used to map each word before creating
* the wordsFilter.
* @return {wordsFilter} object containg `set()` and `exclude()` functions for `words`.
* @example
* var stopWords = [ 'This', 'That', 'Are', 'Is', 'Was', 'Will', 'a' ];
* var myFilter = returnWordsFilter( stopWords, [ string.lowerCase ] );
* [ 'this', 'is', 'a', 'cat' ].filter( myFilter.exclude );
* // -> [ 'cat' ]
*/
var returnWordsFilter = function ( words, mappers ) {
var mappedWords = words;
var givenMappers = mappers || [];
givenMappers.forEach( function ( m ) {
mappedWords = mappedWords.map( m );
} );
mappedWords = new Set( mappedWords );
var exclude = function ( t ) {
return ( !( mappedWords.has( t ) ) );
}; // exclude()
var set = function () {
return mappedWords;
}; // set()
return {
set: set,
exclude: exclude
};
}; // returnWordsFilter()
module.exports = returnWordsFilter;
