js 图片压缩插件image-conversion使用

npm i image-conversion --save
import * as imageConversion from 'image-conversion'

//this.previewSrc需要转换的url  
 //压缩以后的图片 
//imageConversion.compress(data, 0.5) 数字为压缩率1到0.01   
this.downloadImageFile(this.previewSrc, function(data) {
        imageConversion.compress(data, 0.5).then(res => {
          const reader = new FileReader()
          reader.readAsDataURL(res)
          reader.onload = function(e) {
            that.compressSrc = e.target.result
          }
        })
      }),
downloadImageFile(url, callback) {
      fetch(url).then(res => {
        res.blob().then(myBlob => {
          // console.log(myBlob)
          callback(blobToFile(myBlob))
        })
      })
    },