BASE64と画像間の変換

const fsm = wx.getFileSystemManager();
const FILE_BASE_NAME = 'tmp_base64src'; //自定义文件名

function base64src(base64data, cb) {
  console.log(base64data)
  const [, format, bodyData] = /data:image\/(\w+);base64,(.*)/.exec(base64data) || [];
  if (!format) {
    return (new Error('ERROR_BASE64SRC_PARSE'));
  }
  const filePath = `${wx.env.USER_DATA_PATH}/${FILE_BASE_NAME}.${format}`;
  const buffer = wx.base64ToArrayBuffer(bodyData);
  fsm.writeFile({
    filePath,
    data: buffer,
    encoding: 'binary',
    success() {
      cb(filePath);
    },
    fail() {
      return (new Error('ERROR_BASE64SRC_WRITE'));
    },
  });
};

function base64({url,type}) {
  return new Promise((resolve, rejiect) => {
    wx.request({
      url: url,
      responseType: 'arraybuffer',
      success: res => {
        let base64Url = wx.arrayBufferToBase64(res.data); //把arraybuffer转成base64
        // resolve('data:image/' + type.toLocaleLowerCase() + ';base64,' + base64Url)
        resolve(base64Url)
      }
    });
  })
};

export { base64src, base64 };