Course · Section 16: Asynchronous JavaScript: Promises, Async/Await, and AJAX · Lecture 263: Promises and the Fetch API
Implement `chainAdd(n)` returning a promise that resolves `n`, adds 1, then doubles the result, using `.then` chaining.
+ 1 hidden test run on Submit.
Each .then transforms the resolved value, composing add-one then double.
Run your code to see results.