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Quiz Questions

What is the extent of your experience with Promises and/or their polyfills?

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Possess working knowledge of it. A promise is an object that may produce a single value sometime in the future: either a resolved value or a reason that it's not resolved (e.g., a network error occurred). A promise may be in one of 3 possible states: fulfilled, rejected, or pending. Promise users can attach callbacks to handle the fulfilled value or the reason for rejection.

Some common polyfills are $.deferred, Q and Bluebird but not all of them comply with the specification. ES2015 supports Promises out of the box and polyfills are typically not needed these days.

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