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Asynchronous JavaScript: JavaScript: Uncharted

Courses JavaScriptAsynchronous JavaScript

Asynchronous JavaScript

Schedule callbacks, work with promises, write readable awaited flows, and coordinate independent jobs.

JavaScript
Unit 16 of 20
20 lessons
184 min
420 XP

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Lessons

20 total

1The Kettle and the ToastCompare blocking and overlapping plans for two independent kitchen tasks.InteractiveConcept6 min20 XPOpen
2Later, with setTimeoutSchedule a callback with setTimeout and observe synchronous output first.CodeConcept8 min20 XPOpen
3Zero Is Not NowPredict output when a zero-delay timer waits behind synchronous work.InteractiveConcept7 min20 XPOpen
4Callbacks for LaterPass follow-up work as a callback and run it after a delay.CodeConcept9 min20 XPOpen
5The Pyramid of DoomNest three dependent timer callbacks and recognize the resulting rightward drift.CodeConcept10 min20 XPOpen
6A Promise of PizzaConsume a fulfilled promise with then and use its eventual value.CodeConcept8 min20 XPOpen
7Make Your Own PromiseWrap setTimeout in a wait function that returns a promise.CodeConcept10 min20 XPOpen
8Chains, Not PyramidsFlatten nested promise handlers into a returned then chain.CodeConcept10 min20 XPOpen
9catch the LetdownHandle a rejected promise with catch and keep later work running.CodeConcept8 min20 XPOpen
10Promise vs TimerPredict how a promise handler interleaves with synchronous code and a timer.InteractiveConcept7 min20 XPOpen
11async/await, at LastRewrite a promise chain as an async function with sequential awaits.CodeConcept10 min20 XPOpen
12await with a NetCatch a rejected awaited operation with try and catch.CodeConcept10 min20 XPOpen
13One by One, or TogetherContrast sequential awaits with starting two independent promises before awaiting.CodeConcept11 min20 XPOpen
14Promise.all HandsStart several preparations together and gather their values with Promise.all.CodeConcept10 min20 XPOpen
15First Past the PostUse Promise.race to enforce a timeout around asynchronous work.CodeConcept10 min20 XPOpen
16Refactor the PyramidArrange the steps for converting nested callbacks into an async and await sequence.InteractiveConcept7 min20 XPOpen
17Kitchen RushCoordinate a changing order with Promise.all and await an exact final report.CodePractice12 min20 XPOpen
18Mixed-Order PredictionsPredict one output sequence containing synchronous, promise, and timer work.InteractiveConcept7 min20 XPOpen
19Retry PolitelyRetry a deterministic flaky request with a capped async loop.CodePractice12 min20 XPOpen
20Async Mastery CheckCoordinate timer-backed jobs, recover failures, and preserve observable output order.CodeMastery check12 min40 XPOpen

Errors and Robustness How JavaScript Runs