When I call this promise, the output does not match with the sequence of function calls. The .then comes before the .catch, even though the promise with .then was being called after. What is the reason for that?
const verifier = (a, b) =>
new Promise((resolve, reject) => (a > b ? resolve(true) : reject(false)));
verifier(3, 4)
.then((response) => console.log("response: ", response))
.catch((error) => console.log("error: ", error));
verifier(5, 4)
.then((response) => console.log("response: ", response))
.catch((error) => console.log("error: ", error));output
node promises.js
response: true
error: false
Promise.resolve()
.then(() => console.log('a1'))
.then(() => console.log('a2'))
.then(() => console.log('a3'))
Promise.resolve()
.then(() => console.log('b1'))
.then(() => console.log('b2'))
.then(() => console.log('b3'))Instead of output a1, a2, a3, b1, b2, b3 you will see a1, b1, a2, b2, a3, b3 because of the same reason - every then returns a promise and it goes to the end of the event-loop queue. So we can see this "promise race". The same is when there are some nested promises.