Why do both Promise's then & catch callbacks get called?

Question

I have the following code and when it\'s executed, it returns both \"rejected\" and \"success\":

// javascript promise
var          


        

Answer 1

For those who had a successfully resolved promise and a chain ordered like .then > .catch, but still had both your then and catch called, it may be because your then had an error-throwing bug that you can't see unless you explicitly console the error in your catch. That's one of my pet-peeves with Promises absorbing errors even in strict mode.

const promise = new Promise(resolve => resolve())
.then(() => {
    console.log('then');
    not.defined = 'This causes the catch to fire even though the original promise resolved successfully.';
})
.catch((e) => {
    console.log('catch');
    // console.error(e);
});