A promise represents an operation that hasn`t completed yet, but is expected in the future.
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a Promise represents an operation that hasn`t completed yet, but is expected in the future
Promise is a global function
- instantiating it without params throws
- expects a function as parameter
- resolve a promise by calling the
resolve function given as first parameter
resolve function can return a value, that is consumed by the
- rejecting a promise is done by calling the callback given as 2nd parameter
an asynchronous promise
- can resolve later, also by calling the first callback
- reject it at some later point in time, calling the 2nd callback
test library (mocha here) support for promises
- just returning the promise makes the test library check that the promise resolves
A well understandable description of the states a promise can be in.