vue 利用原声input上传图片并预览并删除

<template>
<div class="com-upload-img">
<div class="img_group">
<div v-if="allowAddImg" class="img_box">
<input type="file" accept="image/*" multiple="multiple" @change="changeImg($event)">
<div class="filter" />
</div>
<div v-for="(item,index) in imgArr" :key="index" class="img_box">
<div class="img_show_box">
<img :src="item" alt="">
<i class="img_delete" @click="deleteImg(index)" />
<!-- <i class="img_delete" @click="imgArr.splice(index,1)"></i> -->
</div>
</div>
</div>
</div>
</template>

<script>
export default {
name: 'ComUpLoad',
data() {
return {
imgData: '',
imgArr: [],
imgSrc: '',
allowAddImg: true
}
},
methods: {
changeImg: function(e) {
var _this = this
var imgLimit = 1024
var files = e.target.files
var image = new Image()
if (files.length > 0) {
var dd = 0
var timer = setInterval(function() {
if (files.item(dd).type !== 'image/png' && files.item(dd).type !== 'image/jpeg' && files.item(dd).type !== 'image/gif') {
return false
}
if (files.item(dd).size > imgLimit * 102400) {
// to do sth
} else {
image.src = window.URL.createObjectURL(files.item(dd))
image.onload = function() {
// 默认按比例压缩
var w = image.width
var h = image.height
var scale = w / h
w = 200
h = w / scale
// 默认图片质量为0.7，quality值越小，所绘制出的图像越模糊
var quality = 0.7
// 生成canvas
var canvas = document.createElement('canvas')
var ctx = canvas.getContext('2d')
// 创建属性节点
var anw = document.createAttribute('width')
anw.nodeValue = w
var anh = document.createAttribute('height')
anh.nodeValue = h
canvas.setAttributeNode(anw)
canvas.setAttributeNode(anh)
ctx.drawImage(image, 0, 0, w, h)
var ext = image.src.substring(image.src.lastIndexOf('.') + 1).toLowerCase()// 图片格式
var base64 = canvas.toDataURL('image/' + ext, quality)
// 回调函数返回base64的值
if (_this.imgArr.length <= 4) {
_this.imgArr.unshift('')
_this.imgArr.splice(0, 1, base64)// 替换数组数据的方法，此处不能使用：this.imgArr[index] = url;
if (_this.imgArr.length >= 5) {
_this.allowAddImg = false
}
}
}
} if (dd < files.length - 1) {
dd++
} else {
clearInterval(timer)
}
}, 1000)
}
},
deleteImg: function(index) {
this.imgArr.splice(index, 1)
if (this.imgArr.length < 5) {
this.allowAddImg = true
}
}
}
}
</script>