In this chapter's preceding recipes, we've been creating new promise objects with the constructor. This gets the jobs done, but it creates a problem. The first callback in the promise chain has a different shape than the subsequent callbacks.
In the first callback, the arguments are the resolve and reject functions that trigger the subsequent then or catch callbacks. In subsequent callbacks, the returned value is propagated down the chain, and thrown errors are captured by catch callbacks. This difference adds mental overhead. It would be nice to have all of the functions in the chain behave in the same way.
In this recipe, we'll see how to use Promise.resolve to start a promise chain.
