Promises VIII: Old Callback API

Published by Isaac Pak in
functional_programming

You may run into some old asynchronous API that requires you to pass in a callback. Take the setTimeout() function for example:

setTimeout(() => saySomething("1 second passed"), 1000)

What if an error occured in the saySomething() function. How could you handle it? Wrap it with a Promise!

There are some elements missing in the wait function, it should return a promise. Create an error handler and assign the error to ERR inside the handler.

Notes

  • Do not change the function saySomething().
  • You should not have to erase any of the existing code.
  • Check Resources if you get stuck.
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