lib/pairs-list.js

  1. /**
  2.  *@classdesc Controler of paired items.
  3.  * @class
  4.  */
  5. export class MemoryPairsList extends Array {
  6.   /**
  7.    * Apply visual changes on paired elements.
  8.    * @param {HTMLCanvasElement} canvas Set a pair as found.
  9.    */
  10.   checkMark(canvas) {
  11.     const ctx = canvas.getContext('2d');
  12.     const w = canvas.offsetWidth;
  13.     const h = canvas.offsetHeight;
  14.     const img = this.getImage(canvas);
  15.     ctx.clearRect(0, 0, w, h);
  16.     ctx.globalAlpha = 0.25;
  17.     ctx.drawImage(
  18.       img,
  19.       0,
  20.       0,
  21.       parseInt(img.width),
  22.       parseInt(img.height),
  23.       0,
  24.       0,
  25.       w,
  26.       h
  27.     );
  28.     ctx.globalAlpha = 1;
  29.     ctx.save();
  30.   }
  31.   /**
  32.    *
  33.    * @param {HTMLCanvasElement} canvas Canvas element to be checked.
  34.    * @return {boolean} If given canvas has already a known pair.
  35.    */
  36.   hasPair(canvas) {
  37.     const self = this;
  38.     let hasPair = false;
  39.     self.forEach((c) => {
  40.       if (c[0] === canvas) {
  41.         hasPair = true;
  42.       }
  43.       if (c[1] === canvas) {
  44.         hasPair = true;
  45.       }
  46.     });
  48.     return hasPair;
  49.   }
  51.   /**
  52.    *
  53.    * @param {Array} state Holds info object for both open cards.
  54.    * @return {boolean} Are both canvas in given state pair or not.
  55.    */
  56.   arePairs(state) {
  57.     const one = state[0];
  58.     const two = state[1];
  59.     const self = this;
  60.     let matches = false;
  61.     self.forEach((c) => {
  62.       if (c[0] === one || c[1] === one) {
  63.         if (c[0] === two || c[1] === two) {
  64.           matches = true;
  65.           this.checkMark(one);
  66.           this.checkMark(two);
  67.         }
  68.       }
  69.     });
  70.     return matches;
  71.   }
  73.   /**
  74.    * find image of given canvas.
  75.    * @param {HTMLCanvasElement} canvas image of the given canvas.
  76.    * @return {HTMLImageElement} Image for the given canvas.
  77.    */
  78.   getImage(canvas) {
  79.     let img;
  80.     this.forEach((c) => {
  81.       if (c[0] === canvas || c[1] === canvas) {
  82.         img = c[2];
  83.       }
  84.     });
  85.     return img;
  86.   }
  87. }