js 压缩jpg图片

推荐库：

​​GitHub - fengyuanchen/compressorjs: JavaScript image compressor.​​

vant 上传压缩示例：

npm i  compressorjs -s
import Compressor from 'compressorjs';
before-read 回调中：：
  beforeRead(file){
      let that = this
      return new Promise((resolve) => {
        // compressorjs 默认开启 checkOrientation 选项
        // 会将图片修正为正确方向
        new Compressor(file, {
          quality: 0.3,
          success(result){
            // that.fileSize = result.size
            resolve(result);
          },
          error(err) {
            console.log(err.message);
          },
        });
      });
    },