element-ui upload 图片格式验证 ，文件验证

handleAvatarSuccess(res, file) {
      this.formInline.logFile = file.raw
      this.imageUrl = URL.createObjectURL(file.raw)
    },
    beforeAvatarUpload(file) {
      // const isJPG = file.type === 'image/jpeg'
      var testmsg = /^image/(jpeg|png|jpg)$/.test(file.type)
      const isLt5M = file.size / 1024 / 1024 < 5
      if (!testmsg) {
        this.$message.error('上传图片格式不对!')
        return
      }
      if (!isLt5M) {
        this.$message.error('上传头像图片大小不能超过 2MB!')
      }
      return testmsg && isLt5M
    }

<el-upload
              class="avatar-uploader"
              action=""
              :show-file-list="false"
              :on-change="uploadChange">
              <img
                v-if="imageUrl"
                :src="imageUrl"
                class="avatar">
              <i
                v-else
                class="el-icon-plus avatar-uploader-icon" />
</el-upload>

uploadChange(file) {
      this.addInfoForm.files.push(file)
      this.imgChanged = true
      // 图片显示前做一下判断
      const IMG_ALLOWD = ['jpeg', 'jpg', 'gif', 'png']
      const imgType = file.raw.type.split('/')[1]
      const imgSize = file.size / 1024 / 1024
      // 判断图片格式
      if (IMG_ALLOWD.indexOf(imgType) === -1) {
        this.$message.warning('上传图片格式错误')
        this.imageUrl = null
      } else if (imgSize >= 400) {
        // 判断图片大小
        this.$message.warning('图片大小大于5M')
        this.imageUrl = null
      } else {
        // 成功
        this.file = file.raw
        this.imageUrl = URL.createObjectURL(this.file)
      }
    }