An async function marks work that depends on asynchronous values. It returns a promise, and `await` lets the function pause for a result without blocking the UI. section 6.4.1
Async/await provides built-in language support for coordinating generators and promises, avoiding a reusable helper that would otherwise resume a generator as promises settle. section 6.4 section 6.4.1
Fetch dependent mission data
Await JSON for a ninja, that ninja’s missions, and a mission’s details in sequence; use try/catch to handle a failed request. section 6.4 section 6.4.1
