Tricks about Handle Promise Exception You May Don’t Know

How to do in nested Promise?

Photo by Markus Spiske on Unsplash

The Promise always is an important but complex point in JavaScript. But when I review other coders’ ways to handle Promise exceptions, there often has some mistakes. Here, let’s discuss this question.

Handle Promise Exception with Try Catch

No more words, let’s look at a code snippet:

What is the result after running the above code? Can the try-catch statement really catch the exception which was thrown by the Promise object?

Here is the running result:

We can find that the try-catch statement can not catch the exception thrown in the foo function.

Why?

Before we discuss the question, we should understand the execution order of the above code.