Some random uncompleted huffman tree implementation

huffman.js

// Priority stack implementation over here https://github.com/avdg/screeps/blob/master/extensions/tools/library/priorityStack.js
// Assume AI.priorityStack = require(<path to priorityQueue>);

/**
 * A basic huffman tree compression algorithm
 *
 * @param input String Input to convert
 *
 * @return string
 */
function packHuffman(input) {
    var frequency = {};
    var list = new AI.priorityStack(function(a, b) {
        return b.frequency - a.frequency;
    });
    var output = "";

    // Count input
    for (var i = 0; i < input.length; i++) {
        if (frequency[input[i]] === undefined) {
            frequency[input[i]] = 1;
        } else {
            frequency[input[i]]++;
        }
    }

    // Count frequency
    for (var char in frequency) {
        list.push({
            value: char,
            frequency: frequency[char]
        });
    }

    // Build huffman tree
    while (list.length > 1) {
        var node = {
            nodes: [list.pop(), list.pop()],
        };
        node.frequency = node.nodes[0].frequency + node.nodes[1].frequency;
        list.push(node);
    }

    // Only 1 item in tree, which is the huffman tree
    list = list.pop();

    // Convert huffman codes for encoding
    var table = {};
    var chars = [];
    (function iterate (l, prefix) {
        if (l.value === undefined) {
            iterate(l.nodes[0], prefix + "0");
            iterate(l.nodes[1], prefix + "1");
        } else {
            console.log('"' + l.value + '" with frequency ' + l.frequency + ': ' + prefix);
            chars.push(l.value);
            table[l.value] = prefix;
        }
    })(list, "");

    // Encode encode data- TODO this requires some 1/0 math wonders

    // Encode string data itself - TODO this requires some 1/0 math wonders
    for (var i = 0; i < input.length; i++) {
        // TODO Yeah, convert that characters into bits!

        // TODO Yeah, add those bits into a bitstring if needed!
    }

    // Build encoder data
}