ReactJS和Promise：那么如何调用catch？

Question

So, I have got an action creator (that returns a function - I use redux-thunk). Inside the function the creator returns, I call a dispatch method and chain the then and catch methods. Here how it looks like:

export function actionCreator(someData) {
    (dispath, getState) => {
        return dispatch(someAction)
        .then(resp => {
            //do something
            // GO TO CATCH
        })
        .catch(err => {
            return err;
        })
    }
}

You see the GO TO CATCH comment over there? So, how can I go to the catch block from there?

Thank you!

Answer 1

If you want to jump from the body of a .then() to the following .catch() , the easiest way is to throw an error:

throw new Error('I meant to blow up here.');

The error you throw is what will be passed to the body of the .catch() (the err variable, in your case).

Please note that your example already looks suspect though: your catch block is catching an error and then returning it as if the error was a regular value, which means any upstream promise-based handling will assume the dispatch was successful. Are you sure that's what you want?