Promises for cleaner async in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a new Promise that resolves with 'Done'.

Node.js

const myPromise = new Promise((resolve, reject) => {
  resolve([1]);
});

Drag options to blanks, or click blank then click option'

ADone

Breject

Cresolve

D'Done'

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the string

Using reject instead of resolve

The Promise resolves with the string 'Done', so it must be in quotes.

2fill in blank

medium

Complete the code to handle the Promise result with then().

Node.js

myPromise.[1](result => {
  console.log(result);
});

Drag options to blanks, or click blank then click option'

Athen

Bcatch

Cfinally

Dresolve

Attempts:

3 left

💡 Hint

Common Mistakes

Using catch instead of then for success

Trying to use resolve as a method

The then() method is used to handle the resolved value of a Promise.

3fill in blank

hard

Fix the error in the Promise chain to catch errors.

Node.js

myPromise.then(result => {
  console.log(result);
}).[1](error => {
  console.error(error);
});

Drag options to blanks, or click blank then click option'

Athen

Bfinally

Ccatch

Dresolve

Attempts:

3 left

💡 Hint

Common Mistakes

Using then instead of catch for errors

Using finally to catch errors

The catch() method handles errors in the Promise chain.

4fill in blank

hard

Fill both blanks to create a Promise that rejects on error and handle it.

Node.js

const errorPromise = new Promise((resolve, reject) => {
  if (somethingWrong) {
    reject([1]);
  } else {
    resolve('Success');
  }
});

errorPromise.[2](error => {
  console.log(error);
});

Drag options to blanks, or click blank then click option'

A'Error occurred'

Bcatch

Cthen

D'Success'

Attempts:

3 left

💡 Hint

Common Mistakes

Using resolve instead of reject

Using then instead of catch for errors

The Promise rejects with an error message string, and catch() handles the rejection.

5fill in blank

hard

Fill all three blanks to create a Promise, handle success and error, and finally log done.

Node.js

const promise = new Promise((resolve, reject) => {
  if (isReady) {
    resolve([1]);
  } else {
    reject([2]);
  }
});

promise
  .then(result => console.log(result))
  .catch(error => console.error(error))
  .[3](() => console.log('Done'));

Drag options to blanks, or click blank then click option'

A'All good'

B'Failed'

Cfinally

Dcatch

Attempts:

3 left

💡 Hint

Common Mistakes

Using catch instead of finally for the last step

Forgetting quotes around messages

The Promise resolves with 'All good', rejects with 'Failed', and finally() runs after either case.