Function callbackWrapper

javascript/src/image.js:386–396

(thumbId, opt_error)

      ee.Image.prototype.getThumbURL, arguments);
  if (args['callback']) {
    const callbackWrapper = (thumbId, opt_error) => {
      let thumbUrl = '';
      if (opt_error === undefined) {
        try {
          thumbUrl = ee.data.makeThumbUrl(thumbId);
        } catch (e) {
          opt_error = String(e.message);
        }
      }
      args['callback'](thumbUrl, opt_error);
    };
    this.getThumbId(args['params'], callbackWrapper);
  } else {
    return ee.data.makeThumbUrl(