How to fix “‘throw’ of exception caught locally”?

Contrary to James Thorpe’s opinion, I slightly prefer the pattern of throwing. I don’t see any compelling reason to treat local errors in the try block any differently from errors that bubble up from deeper in the call stack… just throw them. In my opinion, this is a better application of consistency.

Because this pattern is more consistent, it naturally lends itself better to refactoring when you want to extract logic in the try block to another function that is perhaps in another module/file.

// main.js
try {
  if (!data) throw Error('missing data')
} catch (error) {
  handleError(error)
}

// Refactor...

// validate.js
function checkData(data) {
  if (!data) throw Error('missing data')
}

// main.js
try {
  checkData(data)
} catch (error) {
  handleError(error)
}

If instead of throwing in the try block you handle the error, then the logic has to change if you refactor it outside of the try block.

In addition, handling the error has the drawback of making you remember to return early so that the try block doesn’t continue to execute logic after the error is encountered. This can be quite easy to forget.

try {
  if (!data) {
    handleError(error)
    return // if you forget this, you might execute code you didn't mean to. this isn't a problem with throw.
  }
  // more logic down here
} catch (error) {
  handleError(error)
}

If you’re concerned about which method is more performant, you shouldn’t be. Handling the error is technically more performant, but the difference between the two is absolutely trivial.

Consider the possibility that WebStorm is a bit too opinionated here. ESLint doesn’t even have a rule for this. Either pattern is completely valid.