javascriptのマウスホバーイベントについて

前提

javascriptを使って画像にグリッチエフェクトをかけることが出来ましたが、マウスホバー時のみエフェクトをかけたいです。
どこにどのようにしてaddEventListener()関数を利用すればいいのかわかりません。

実現したいこと

ホバー時のみエフェクトを実行させたい。

該当のソースコード

html
1<a href="" data-js="glitch-image"><img src="img/sample01.png" alt="sample01"></a>

css
1[data-js="glitch-image"] {
2  position: relative;
3  width: 100%;
4}
5[data-js="glitch-image"] canvas {
6  position: absolute;
7  top: 0;
8  left: 0;
9  z-index: 1;
10}

javascript
1(function (window) {
2  'use strict';
3
4  let _canvas, _context;
5
6  let _image, _imageData;
7
8  const effectList = [function glitch(context, width, height) {
9    const imageData = context.getImageData(0, 0, width, height);
10    const data = imageData.data;
11    const length = width * height;
12    const factor = Math.random() * 10;
13    let randR = Math.floor(Math.random() * factor);
14    let randG = Math.floor(Math.random() * factor) * 3;
15    let randB = Math.floor(Math.random() * factor);
16
17    for (let i = 0; i < length; i++) {
18      let r = data[(i + randR) * 4];
19      let g = data[(i + randG) * 4 + 1];
20      let b = data[(i + randB) * 4 + 2];
21      if (r + g + b == 0) r = g = b = 255;
22      data[i * 4] = r;
23      data[i * 4 + 1] = g;
24      data[i * 4 + 2] = b;
25      data[i * 4 + 3] = 255;
26    }
27
28    context.putImageData(imageData, 0, 0);
29  }, function glitchWave(context, width, height) {
30    const renderLineHeight = Math.random() * height;
31    const cuttingHeight = 5;
32    const imageData = context.getImageData(0, renderLineHeight, width, cuttingHeight);
33    context.putImageData(imageData, 0, renderLineHeight - 10);
34  }, function glitchSlip(context, width, height) {
35    const waveDistance = 100;
36    const startHeight = height * Math.random();
37    const endHeight = startHeight + 30 + Math.random() * 40;
38
39    for (let h = startHeight; h < endHeight; h++) {
40      if (Math.random() < .1) h++;
41      let imageData = context.getImageData(0, h, width, 1);
42      context.putImageData(imageData, Math.random() * waveDistance - waveDistance * .5, h);
43    }
44  }, function glitchColor(context, width, height) {
45    const waveDistance = 30;
46    const startHeight = height * Math.random();
47    const endHeight = startHeight + 30 + Math.random() * 40;
48    const imageData = context.getImageData(0, startHeight, width, endHeight);
49    const length = width * height;
50    let data = imageData.data;
51    let r = 0;
52    let g = 0;
53    let b = 0;
54
55    for (let i = 0; i < length; i++) {
56      if (i % width === 0) {
57        r = i + Math.floor((Math.random() - .5) * waveDistance);
58        g = i + Math.floor((Math.random() - .5) * waveDistance);
59        b = i + Math.floor((Math.random() - .5) * waveDistance);
60      }
61
62      data[i * 4] = data[r * 4];
63      data[i * 4 + 1] = data[g * 4 + 1];
64      data[i * 4 + 2] = data[b * 4 + 2];
65    }
66
67    context.putImageData(imageData, 0, startHeight);
68  }];
69
70  function init() {
71    const imageBoard = document.querySelector('[data-js="glitch-image"]');
72    _image = imageBoard.querySelector('img');
73    _canvas = document.createElement('canvas');
74    _context = _canvas.getContext('2d');
75    imageBoard.appendChild(_canvas);
76    _imageData = new Image();
77    _imageData.crossOrigin = "Anonymous";
78
79    _imageData.onload = function (event) {
80      window.addEventListener('resize', onResize, false);
81      window.dispatchEvent(new Event('resize'));
82      window.requestAnimationFrame(render);
83    };
84
85    _imageData.src = _image.getAttribute('src');
86  }
87
88  function onResize() {
89    _canvas.width = _image.width;
90    _canvas.height = _image.height;
91  }
92
93  function render(timestamp) {
94    let width = _canvas.width;
95    let height = _canvas.height;
96
97    _context.clearRect(0, 0, width, height);
98
99    _context.drawImage(_imageData, 0, 0, _image.width, _image.height);
100
101    if (.5 < Math.random()) {
102      getRandomValue(effectList)(_context, width, height);
103    }
104
105    window.requestAnimationFrame(render);
106  }
107
108  function getRandomValue(array) {
109    return array[Math.floor(Math.random() * array.length)];
110  }
111  document.addEventListener('DOMContentLoaded', init);
112})(window);