promise/catch-or-return Restriction
What it does
Ensure that each time a then() is applied to a promise, a catch() must be applied as well. Exceptions are made for promises returned from a function.
Why is this bad?
Not catching errors in a promise can cause hard to debug problems or missing handling of error conditions. In the worst case, unhandled promise rejections can cause your application to crash.
Example
Examples of incorrect code for this rule:
javascript
myPromise.then(doSomething);
myPromise.then(doSomething, catchErrors); // catch() may be a little betterExamples of correct code for this rule:
javascript
myPromise.then(doSomething).catch(errors);
function doSomethingElse() {
return myPromise.then(doSomething);
}