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Comment by fjp | Hacker News Reader

I never wrapped my mind around the Promises API, but I have always async/await is much easier to grasp in any language

Maybe because it should have looked like this (personal opinion):

    waitForPromise()
        .then(handleResolve)
        .fail(handleReject)
        .catch(handleException);

But actually looks like this:

    waitForPromise()
        .then(handleResolve, handleReject)
        .catch(handleException);

waitForPromise().catch(foo) is exactly the same thing as waitForPromise().then(undefined, foo). Your first example is essentially the same as:

    waitForPromise()
        .then(handleResolve)
        .catch(handleReject)
        .catch(handleException);

With the exception that if `handleResolve` also throws then that will be picked up by `handleReject`, whereas in `waitForPromise().then(handleResolve, handleReject).catch(handleException)` it won’t.

And you last sentence is exactly describing the issue I have. This merging of exception handling and rejection handling into one function call feels like a bad idea.

As initially I thought catch() is only handling promise rejections. Then suddenly I ended up in the catch() although the Promise resolved fine, just to learn that my handleResolve code threw an exception. Unsurprisingly my handleReject code was not prepared for this.

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