151 lines
4.0 KiB
JavaScript
151 lines
4.0 KiB
JavaScript
/*
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* Fuzzy
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* https://github.com/myork/fuzzy
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*
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* Copyright (c) 2012 Matt York
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* Licensed under the MIT license.
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*/
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(function() {
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var root = this;
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var fuzzy = {};
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// Use in node or in browser
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if (typeof exports !== 'undefined') {
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module.exports = fuzzy;
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} else {
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root.fuzzy = fuzzy;
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}
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// Return all elements of `array` that have a fuzzy
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// match against `pattern`.
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fuzzy.simpleFilter = function(pattern, array) {
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return array.filter(function(string) {
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return fuzzy.test(pattern, string);
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});
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};
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// Does `pattern` fuzzy match `string`?
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fuzzy.test = function(pattern, string) {
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return fuzzy.match(pattern, string) !== null;
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};
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// If `pattern` matches `string`, wrap each matching character
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// in `opts.pre` and `opts.post`. If no match, return null
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fuzzy.match = function(pattern, string, opts) {
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opts = opts || {};
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var patternIdx = 0
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, result = []
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, len = string.length
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, totalScore = 0
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, currScore = 0
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// prefix
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, pre = opts.pre || ''
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// suffix
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, post = opts.post || ''
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// String to compare against. This might be a lowercase version of the
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// raw string
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, compareString = opts.caseSensitive && string || string.toLowerCase()
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, ch, compareChar;
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pattern = opts.caseSensitive && pattern || pattern.toLowerCase();
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// For each character in the string, either add it to the result
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// or wrap in template if it's the next string in the pattern
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for(var idx = 0; idx < len; idx++) {
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ch = string[idx];
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if(compareString[idx] === pattern[patternIdx]) {
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if (pattern[patternIdx] === ' ') {
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// we don't want a space character to accumulate a larger score
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currScore = 1 - idx/200;
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} else {
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// consecutive characters should increase the score more than linearly
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currScore += 1 + currScore - idx/200;
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}
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ch = pre + ch + post;
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patternIdx += 1;
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} else {
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currScore = 0;
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}
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totalScore += currScore;
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if (compareString[idx] === ' ') {
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// we don't want characters after a space to accumulate a larger score
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currScore = 0;
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}
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result[result.length] = ch;
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}
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// return rendered string if we have a match for every char
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if(patternIdx === pattern.length) {
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return {rendered: result.join(''), score: totalScore};
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}
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return null;
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};
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// The normal entry point. Filters `arr` for matches against `pattern`.
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// It returns an array with matching values of the type:
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//
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// [{
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// string: '<b>lah' // The rendered string
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// , index: 2 // The index of the element in `arr`
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// , original: 'blah' // The original element in `arr`
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// }]
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//
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// `opts` is an optional argument bag. Details:
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//
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// opts = {
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// // string to put before a matching character
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// pre: '<b>'
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//
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// // string to put after matching character
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// , post: '</b>'
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//
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// // Optional function. Input is an entry in the given arr`,
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// // output should be the string to test `pattern` against.
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// // In this example, if `arr = [{crying: 'koala'}]` we would return
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// // 'koala'.
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// , extract: function(arg) { return arg.crying; }
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// }
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fuzzy.filter = function(pattern, arr, opts) {
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if(!arr || arr.length === 0) {
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return []
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}
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if (typeof pattern !== 'string') {
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return arr
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}
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opts = opts || {};
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return arr
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.reduce(function(prev, element, idx, arr) {
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var str = element;
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if(opts.extract) {
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str = opts.extract(element);
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}
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var rendered = fuzzy.match(pattern, str, opts);
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if(rendered != null) {
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prev[prev.length] = {
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string: rendered.rendered
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, score: rendered.score
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, index: idx
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, original: element
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};
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}
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return prev;
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}, [])
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// Sort by score. Browsers are inconsistent wrt stable/unstable
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// sorting, so force stable by using the index in the case of tie.
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// See http://ofb.net/~sethml/is-sort-stable.html
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.sort(function(a,b) {
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var compare = b.score - a.score;
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if(compare) return compare;
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return a.index - b.index;
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});
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};
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}());
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