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JavaScript Asynchronous Programming with JavaScript Understanding Promises Promises Review

Wendy Cortes
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Wendy Cortes
Full Stack JavaScript Techdegree Graduate 15,450 Points

For the example of mathPromise, why .then(addFive) and not .then(addfive(value))

for this part:

const value = 5; mathPromise .then(addFive) .then(double) .then(finalValue) .catch( err => console.log(err) )

How are we calling the functions inside the methods without including the parameter value?

1 Answer

Steven Parker
Steven Parker
218,636 Points

Just naming the function doesn't call it, it passes it to the handler which will call it later when the "then" condition is satisfied. At that time, it will be passed the value which the "then" is waiting for.

It wouldn't make sense to call it right now since the value needed to pass to it isn't available yet.