@quantlab/handsontable/test/unit/utils/dataStructures/LinkedList.spec.js

Spreadsheet-like data grid editor that provides copy/paste functionality compatible with Excel/Google Docs

import LinkedList, {NodeStructure} from 'handsontable/utils/dataStructures/linkedList';
/**
 * Refactored implementation of LinkedList tests by Github user Jakehp
 * (part of javascript-algorithms project - all project contributors at repository website)
 *
 * Link to repository: https://github.com/mgechev/javascript-algorithms
 */

describe('Node', () => {
  it('should be a constructor function', () => {
    expect(typeof NodeStructure).toBe('function');
  });

  it('should construct properly', () => {
    var node = new NodeStructure('data');

    expect(node.data).toBe('data');
    expect(node.next).toBe(null);
    expect(node.prev).toBe(null);
  });
});

describe('Linked List', () => {
  it('should be a constructor function', () => {
    expect(typeof LinkedList).toBe('function');
  });

  it('should push properly', () => {
    var linkedList = new LinkedList();

    linkedList.push(1);
    linkedList.push(2);
    linkedList.push(3);
    linkedList.push(4);
    linkedList.push(5);

    expect(linkedList.first.data).toBe(1);
    expect(linkedList.first.next.data).toBe(2);
    expect(linkedList.first.next.next.data).toBe(3);
    expect(linkedList.first.next.next.next.data).toBe(4);
    expect(linkedList.first.next.next.next.next.data).toBe(5);
    expect(linkedList.last.data).toBe(5);
  });

  it('should pop properly', () => {
    var linkedList = new LinkedList();

    linkedList.push(1);
    linkedList.push(2);
    linkedList.push(3);
    linkedList.push(4);
    linkedList.push(5);

    expect(linkedList.pop().data).toBe(5);
    expect(linkedList.pop().data).toBe(4);
    expect(linkedList.pop().data).toBe(3);
    expect(linkedList.pop().data).toBe(2);
    expect(linkedList.pop().data).toBe(1);
  });

  it('should shift properly', () => {
    var linkedList = new LinkedList();

    linkedList.push(1);
    linkedList.push(2);
    linkedList.push(3);
    linkedList.push(4);
    linkedList.push(5);

    expect(linkedList.shift().data).toBe(1);
    expect(linkedList.shift().data).toBe(2);
    expect(linkedList.shift().data).toBe(3);
    expect(linkedList.shift().data).toBe(4);
    expect(linkedList.shift().data).toBe(5);
  });

  it('should reverse properly', () => {
    var linkedList = new LinkedList();

    linkedList.push(1);
    linkedList.push(2);
    linkedList.push(3);
    linkedList.push(4);
    linkedList.push(5);
    linkedList.reverse();

    expect(linkedList.shift().data).toBe(5);
    expect(linkedList.shift().data).toBe(4);
    expect(linkedList.shift().data).toBe(3);
    expect(linkedList.shift().data).toBe(2);
    expect(linkedList.shift().data).toBe(1);
  });

  it('should recursive reverse properly', () => {
    var linkedList = new LinkedList();

    linkedList.push(1);
    linkedList.push(2);
    linkedList.push(3);
    linkedList.push(4);
    linkedList.push(5);
    linkedList.recursiveReverse();

    expect(linkedList.shift().data).toBe(5);
    expect(linkedList.shift().data).toBe(4);
    expect(linkedList.shift().data).toBe(3);
    expect(linkedList.shift().data).toBe(2);
    expect(linkedList.shift().data).toBe(1);
  });

  it('should unshift properly', () => {
    var linkedList = new LinkedList();

    linkedList.push(1);
    linkedList.push(2);
    linkedList.push(3);
    linkedList.push(4);
    linkedList.push(5);
    linkedList.unshift(3);

    expect(linkedList.shift().data).toBe(3);
    expect(linkedList.shift().data).toBe(1);
    expect(linkedList.shift().data).toBe(2);
    expect(linkedList.shift().data).toBe(3);
    expect(linkedList.shift().data).toBe(4);
    expect(linkedList.shift().data).toBe(5);
  });

  it('should properly check for existing cycle', () => {
    var linkedList = new LinkedList();
    var last = new NodeStructure(2);
    var first = new NodeStructure(1);
    last.next = first;
    last.prev = first;
    first.next = last;
    first.prev = last;
    linkedList.first = first;
    linkedList.last = last;

    expect(linkedList.hasCycle()).toBe(true);
  });

  it('should properly check for non existing cycle', () => {
    var linkedList = new LinkedList();

    linkedList.push(1);
    linkedList.push(2);
    linkedList.push(3);
    linkedList.push(4);
    linkedList.push(5);

    expect(linkedList.hasCycle()).toBe(false);
  });

  it('should inorder properly', () => {
    var linkedList = new LinkedList();

    linkedList.push(1);
    linkedList.push(2);
    linkedList.push(3);
    linkedList.push(4);
    linkedList.push(5);

    var pushedValue = 1;

    function callback(node) {
      expect(node.data).toBe(pushedValue++);
    }

    linkedList.inorder(callback);
  });
});