在撰写本文时(2018-05-15)，Google Apps脚本不支持用于跟踪任务状态的触发器.

As of this writing (2018-05-15), Google Apps Script does not support a trigger to track a task's status.

我怀疑Zapier正在通过Task API轮询任务状态； IE.定期检查任务的状态属性，并在状态更改完成后触发事件.

I suspect that Zapier is polling the status of the task via the Task API; ie. periodically checking the status property of the task and firing an event once the status changes to complete.

您可以将Task API用作GAS中的高级服务(通过基于时间的触发器):

You can do the same (with time-based triggers) using the Task API as an Advanced Service in GAS:

• https://developers.google.com/apps-script/advanced/tasks
• https://developers.google.com/tasks/quickstart/apps-script

• https://developers.google.com/apps-script/advanced/tasks
• https://developers.google.com/tasks/quickstart/apps-script