onImageChanged 这个函数是哪里来的

[wengxianxun]

scanner.onImageChanged && scanner.onImageChanged(res.tempFilePaths[0])

这个函数没找到出处，怎么理解啊

[zh8637688]

on(action, callback) {
  if (actionTypes.indexOf(action) > -1 && typeof (callback) === 'function') {
    this['on' + action] = callback
  }
  return this
}

new CardScanner(this)
  .on('ImageChanged', (imgPath) => {
    console.log(imgPath)
  })