List Data Structure

list.js

function List() {
        this.listSize = 0;
        this.pos = 0;
        this.dataStore = []; // initializes an empty array to store list elements
        this.clear = clear;
        this.find = find;
        this.toString = toString;
        this.insert = insert;
        this.append = append;
        this.remove = remove;
        this.start = start;
        this.end = end;
        this.prev = prev;
        this.next = next;
        this.length = length;
        this.currPos = currPos;
        this.at = at;
        this.getElement = getElement;
        this.length = length;
        this.contains = contains;
    }

    // Push to the end
    function push(element) {
        this.dataStore[this.listSize++] = element; // O(1)
    }

    // Find element in array
    function find(element) {
        for (var i = 0; i < this.dataStore.length; ++i) { // O(n)
            if (this.dataStore[i] == element) {
                return i;
            }
        }
        return -1;
    }

    // Remove element if exists
    function remove(element) {
        var foundAt = this.find(element); // O(n)
        if (foundAt > -1) {
            this.dataStore.splice(foundAt, 1); // O(n)
            --this.listSize;
            return true;
        }
        return false;
    }

    // Get length
    function length() {
        return this.listSize; // O(1)
    }

    // Print the array
    function toString() {
        return this.dataStore; // O(n)
    }

    // Insert the element after
    function insert(element, after) {
        var insertPos = this.find(after); // O(n)
        if (insertPos > -1) {
            this.dataStore.splice(insertPos + 1, 0, element); // O(n)
            ++this.listSize;
            return true;
        }
        return false;
    }

    // Zero the list
    function clear() { // O(1)
        delete this.dataStore;
        this.dataStore = [];
        this.listSize = this.pos = 0;
    }

    // Check if element exists in the list
    function contains(element) {
        for (var i = 0; i < this.dataStore.length; ++i) { // O(n)
            if (this.dataStore[i] == element) {
                return true;
            }
        }
        return false;
    }

    // First
    function start() {
        this.pos = 0; // O(1)
    }

    // last
    function end() {
        this.pos = this.listSize - 1; // O(1)
    }

    // Previus
    function prev() {
        if (this.pos > 0) { // O(1)
            --this.pos;
        }
    }

    // Next
    function next() {
        if (this.pos < this.listSize - 1) { // O(1)
            ++this.pos;
        }
    }

    // Current
    function currPos() {
        return this.pos; // O(1)
    }

    // Go at position
    function at(position) {
        this.pos = position; // O(1)
    }

    // Get current element
    function getElement() {
        return this.dataStore[this.pos]; // O(1)
    }