1---
2title: Promise.all() for Independent Operations
3impact: CRITICAL
4impactDescription: 2-10× improvement
5tags: async, parallelization, promises, waterfalls
6---
7 
8## Promise.all() for Independent Operations
9 
10When async operations have no interdependencies, execute them concurrently using `Promise.all()`.
11 
12**Incorrect (sequential execution, 3 round trips):**
13 
14```typescript
15const user = await fetchUser()
16const posts = await fetchPosts()
17const comments = await fetchComments()
18```
19 
20**Correct (parallel execution, 1 round trip):**
21 
22```typescript
23const [user, posts, comments] = await Promise.all([
24  fetchUser(),
25  fetchPosts(),
26  fetchComments()
27])
28```
29