Autocomplete

autocomplete.js

/**
 * @param {string[]} sentences
 * @param {number[]} times
 */
var AutocompleteSystem = function(sentences, times) {
    this.trie = { letters: {} };
    this.sentences = {};
    this.searchInput = '';
    
    sentences.forEach((sentence, sentenceIdx) => {
        this.addSentence(sentence, times[sentenceIdx]);
    });
    
    this.searchNode = this.trie;
};      

AutocompleteSystem.prototype.addSentence = function (sentence, times) {
    let trieNode = this.trie;
    
    if (sentence in this.sentences === false) {
        if (times == null) { // clean
            this.sentences[sentence] = { sentence, times: 1 };
        } else {
            this.sentences[sentence] = { sentence, times };
        }
    } else this.sentences[sentence].times++;
    
    sentence.split('').forEach((letter, i) => {
        if (letter in trieNode.letters === false) {
            trieNode.letters[letter] = { letters: {} };
        }

        if (i >= sentence.length - 1) {
            trieNode.letters[letter].sentences = [this.sentences[sentence]];
            // add sentence shortcut here
            // for (let i = sentence.length - 1; i >= 0; i--) { 
            // }
        } else {
            trieNode = trieNode.letters[letter];
        }
    });
}

/** 
 * @param {character} c
 * @return {string[]}
 */
AutocompleteSystem.prototype.input = function(c) {
    if (c === '#') {
        this.addSentence(this.searchInput);
        this.searchInput = '';
        this.searchNode = this.trie;
        return [];
    }
    
    this.searchInput += c;
    
    if (c in this.searchNode.letters) {
        this.searchNode = this.searchNode.letters[c];
        return this.getSearchResults();
    } else {
        this.searchNode = { letters: {} };
        return [];
    }
};

AutocompleteSystem.prototype.getSearchResults = function () {
    let resultWords = drillNode(this.searchNode);
    
    function drillNode (searchNode) {
        let resultWords = [];
        if (searchNode && searchNode.sentences)//  return searchNode.sentences;
            resultWords = resultWords.concat(searchNode.sentences);
        
        Object.keys(searchNode.letters).forEach(letter => {
            let letterWords = drillNode(searchNode.letters[letter]);
            if (letterWords && letterWords.length > 0)
                resultWords = resultWords.concat(letterWords);
        });
        
        return resultWords;
    }
    
    resultWords.sort(function (prev, next) {
        let timeDiff = next.times - prev.times;
        if (timeDiff === 0) {
            return prev.sentence.localeCompare(next.sentence);
        }
        return timeDiff;
    })
        return resultWords.map(resultObject => resultObject.sentence).slice(0, 3);
};

/** 
 * Your AutocompleteSystem object will be instantiated and called as such:
 * var obj = new AutocompleteSystem(sentences, times)
 * var param_1 = obj.input(c)
 */