Hash Compression

Assignment 9

by Jake Jernigan

HTML

<form id="form">Enter Phrase.
    <br/>
    <textarea id="phrase" rows="4" cols="50">I want what I want and I know what I want</textarea>
    <br/>
    <input type="button" value="Parse Phrase" id="parse" onClick=parsePhrase();>
</form>
<br/>
<div id="output"></div>

JavaScript

var hashTable = new HashTable(); // Global

function parsePhrase() {
    hashTable.clear();
    var phrase = document.getElementById("phrase").value;
    var phraseAsStringArray = phrase.split(" ");
    var len = phraseAsStringArray.length;

    for (var i = 0; i < len; i++) {
        hashTable.addWord(phraseAsStringArray[i], i + 1);
    }
    
    document.getElementById("output").innerHTML = hashTable.print();
}

function HashTable(obj) {
    this.bins = {};
    this.length = 0;
    for (var p in obj) {
        if (obj.hasOwnProperty(p)) {
            this.bins[p] = obj[p];
            this.length++;
        }
    }

    this.addWord = function(word, index) {
        if (this.hasWord(word)) {
            this.addExistingWord(word, index);
        }
        else {
            this.addNewWord(word, index);
        }
        
       return word;
    }

    this.hasWord = function(word) {
        return this.bins.hasOwnProperty(word);
    }

    this.addNewWord = function(word, index) {
        this.bins[word] = index;
        this.length++;
        return word;
    }

    this.addExistingWord  = function(word, index) {
        var current = this.bins[word];
        this.bins[word] = current + " " + index;
        return word;
    }

    this.print = function() {
        var str = "";

        for (var w in this.bins) {
            if (this.hasWord(w)) {
                str = str + w + ": " + this.bins[w] + "<br/>";
            }
        }

        return str;
    }
    
    this.clear = function() {
        this.bins = {};
        this.length = 0;
    }
}