Vue-Cli的生命周期写法，methods要与data()平级，生命周期函数要与methods平级

<template>
  <h2>复制或剪切图片后以ctrl + V 粘贴</h2>
   <img id="img" src="" alt="">
</template>
 
<script>
export default {
  methods: {
    setPasteImg(){
            //粘贴事件
            document.addEventListener('paste', function(event){
                if (event.clipboardData || event.originalEvent) {
                    var clipboardData = (event.clipboardData || event.originalEvent.clipboardData);
                    if(clipboardData.items){
                        var  blob;
                        for (var i = 0; i < clipboardData.items.length; i++) {
                            if (clipboardData.items[i].type.indexOf("image") !== -1) {
                                blob = clipboardData.items[i].getAsFile();
                            }
                        }
                        var render = new FileReader();
                        render.onload = function (evt) {
                            //输出base64编码
                            var base64 = evt.target.result;
                            document.getElementById('img').setAttribute('src',base64);
                        }
                        render.readAsDataURL(blob);
                    }
 
                }
 
            })
        }
  },
  mounted(){
    this.setPasteImg()
  }
}
</script>
 
<style>
      #img{
            width: 800px;
            box-shadow: 0 0 5px blue;
        }
</style>