What is Promise chaining?

Q: What is Promise chaining?

return fetch(jsonbin) .then((data) => { console.log(data); return fetch(gituser1); //returning a promise }) .then((data) => { console.log(data); return fetch(gituser2); //returning a promise }) .then((data) => { console.log(data); return fetch(gituser3); //returning a promise }) .then((data) => { console.log(data); //returning a promise }) .catch((e) => e);

Difficulty: 5/10

sequential async, error propagation, return values

Promise chaining is the process of linking multiple promises sequentially using the `.then()` method, so that the result of one operation becomes the input for the next. We should return the new promise from the old one on which then will be called.

javascript

Scenario Questions

0-2 years experience

1You need to fetch user data, then their posts, and finally render them. How would you use promise chaining to ensure each step runs after the previous one completes?
2If you return a value from a .then() callback, what does the next .then() receive? Show a short code example.

2-5 years experience

1We have a function that returns a promise, but sometimes it rejects. How would you structure a chain to retry the operation once before propagating the error?

Follow-up Questions

What happens if you forget to return a promise inside a .then?
How does a thrown error inside a .then differ from a rejected promise?
Can you rewrite a promise chain using async/await and what changes?

What is Promise chaining?

Promise chaining is the process of linking multiple promises sequentially using the .then() method, so that the result of one operation becomes the input for the next. We should return the new promise from the old one on which then will be called.

Scenario Questions

Follow-up Questions

What is Promise chaining?

Promise chaining is the process of linking multiple promises sequentially using the .then() method, so that the result of one operation becomes the input for the next. We should return the new promise from the old one on which then will be called.

Scenario Questions

Follow-up Questions

Promise chaining is the process of linking multiple promises sequentially using the `.then()` method, so that the result of one operation becomes the input for the next. We should return the new promise from the old one on which then will be called.

Promise chaining is the process of linking multiple promises sequentially using the `.then()` method, so that the result of one operation becomes the input for the next. We should return the new promise from the old one on which then will be called.