Promises & async

What you'll learn

• The promise model — a value that arrives later, with three states
• How chaining works and why each then returns a new promise
• async and await as a friendlier face on the same promises
• Running work in parallel vs in sequence, and when each is right
• Catching errors in async code without losing them
• How the event loop schedules tasks, microtasks, and your code

1. 01
   Why callbacks weren't enough

   The callback pyramid, lost errors, and the trust problem that promises were built to fix.
   11 min
2. 02
   What a promise is

   A receipt for a value that hasn't arrived yet. Pending, fulfilled, rejected — and why settle is final.
   13 min
3. 03
   then, catch, finally

   Chaining without nesting. Each then is a new promise; returning one flattens it.
   14 min
4. 04
   async / await

   The same promises, written like procedures. Where the function pauses and where it resumes.
   15 min
5. 05
   Parallel vs sequential

   Promise.all, allSettled, race, any. Choosing the right combinator for the job.
   14 min
6. 06
   Errors in async code

   try / catch around await, unhandled rejections, and the rule that keeps you safe.
   14 min
7. 07
   Microtasks and the event loop

   Why your console.log order surprises you. The microtask queue, the macrotask queue, and how they take turns.
   19 min