queue.js

class _Node {
  constructor(data) {
    this.data = data;
    this.next = null;
    this.prev = null;
  }
}

class Queue {
  constructor() {
    this.first = null;
    this.last = null;
  }

  inqueue(data) {
    const animal = new _Node(data);
    if (this.first === null) {
      this.first = animal;
    }
    if (this.last) {
      animal.next = this.last;
      this.last.prev = animal;
    }
    this.last = animal;
  }

  remove() {
    if (this.first === null) {
      return;
    }
    const animal = this.first;
    this.first = animal.prev;

    if (animal === this.last) {
      this.last = null;
    }
    return animal.data;
  }
}

const catQueue = new Queue();
const dogQueue = new Queue();

const helpers = {
  peek: queue => {
    if (queue.first) {
      return queue.first.data;
    }
  }
};

const theDogs = [
  {
    imageURL:
      "http://www.dogster.com/wp-content/uploads/2015/05/Cute%20dog%20listening%20to%20music%201_1.jpg",
    imageDescription:
      "A smiling golden-brown golden retreiver listening to music.",
    name: "Zeus",
    sex: "Male",
    age: 3,
    breed: "Golden Retriever",
    story: "Owner Passed away"
  },
  {
    imageURL: "https://i.imgur.com/xyPtn4m.jpg",
    imageDescription: "Sleeping retreiver.",
    name: "Bailey",
    sex: "Female",
    age: 0,
    breed: "Labrador Retriever",
    story: "Abandoned"
  },
  {
    imageURL: "https://i.imgur.com/JR6noxf.jpg",
    imageDescription: "A confused lab with head cocked to the side",
    name: "Hunter",
    sex: "Male",
    age: 1,
    breed: "Labrador Retriever",
    story: "Owner passed away"
  },
  {
    imageURL: "https://i.imgur.com/f6nA4Zz.png",
    imageDescription: "A husky looking into the camera",
    name: "Lonnie",
    sex: "Male",
    age: 1,
    breed: "Siberian Husky",
    story: "Owner passed away"
  }
];

const theCats = [
  {
    imageURL:
      "https://assets3.thrillist.com/v1/image/2622128/size/tmg-slideshow_l.jpg",
    imageDescription:
      "Orange bengal cat with black stripes lounging on concrete.",
    name: "Fluffy",
    sex: "Female",
    age: 2,
    breed: "Bengal",
    story: "Thrown on the street"
  },
  {
    imageURL: "https://i.imgur.com/RdextKT.jpg",
    imageDescription: "A suspicious cat.",
    name: "Princess",
    sex: "Female",
    age: 5,
    breed: "Persian",
    story: "Found in an alley"
  },
  {
    imageURL: "https://i.imgur.com/UHYngUA.jpg",
    imageDescription: "An orange cat with his mouth open",
    name: "Night",
    sex: "Male",
    age: 1,
    breed: "Orange",
    story: "Found in an alley"
  }
];

module.exports = { catQueue, theCats, dogQueue, theDogs, helpers };