# do

**当 `Observable` 产生某些事件时，执行某个操作**

![](https://4217506537-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MWj545abP2yK86-qksJ%2Fsync%2F482543241f163689f4bf47497ef57321c5d4671b.png?generation=1616819395849815\&alt=media)

当 `Observable` 的某些事件产生时，你可以使用 **do** 操作符来注册一些回调操作。这些回调会被单独调用，它们会和 `Observable` 原本的回调分离。


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