Is Using `.then(function(a){ return a; })` a No-Op for Promises?

Is ".then(function(a){ return a; })" a No-Op for Promises?

.then(function (a) { return a; }) does indeed appear to be a no-op in the context of Promises. As explained in the tutorial you referenced, Promises allow for the chaining of operations. Each operation within the chain can be thought of as a function that takes a Promise as input and returns a Promise as output.

The purpose of the ".then(...)" method is to specify what action should be taken when the preceding Promise resolves. In this case, the function passed to ".then(...)" simply returns the input value without any transformation. This means that the output of the ".then(...)" operation is the same as the input, effectively making it a no-op.

To answer your question directly, yes, the two function calls you provided, with and without the ".then(...)" call, are effectively the same. Both will return the same Promise and can be invoked in the same way.

The reason why the author may have written the code with the ".then(...)" call is a matter of personal preference or misunderstanding. It is generally not considered best practice to include unnecessary code, especially when it can lead to confusion.

Therefore, it is recommended to omit the ".then(function (a) { return a; })" call when it is not actually performing any useful transformation on the Promise value.

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