Rule proposal: no-identical-catch

[dimaMachina]

Description

Same catch statement inside another catch statement can be safely removed

Fail

try {
  if (foo) {
    try {
      for await (const result of value) {
        handleResponse(result);
      }
      setIsFetching(false);
      setSubscription(null);
    } catch (error) {
      setIsFetching(false); // ❌ duplicates can be safely removed
      setResponse(formatError(error)); // ❌ duplicates can be safely removed
      setSubscription(null); // ❌ duplicates can be safely removed
    }
  } else {
    handleResponse(value);
  }
} catch (error) {
  setIsFetching(false);
  setResponse(formatError(error));
  setSubscription(null);
}

Pass

try {
  if (foo) {
    try {
      for await (const result of value) {
        handleResponse(result);
      }
      setIsFetching(false);
      setSubscription(null);
    } catch (error) {
      setIsFetching(false);
      setResponse(someAnotherFunction(error));
      setSubscription(null);
    }
  } else {
    handleResponse(value);
  }
} catch (error) {
  setIsFetching(false);
  setResponse(formatError(error));
  setSubscription(null);
}

Additional Info

real-world example graphql/graphiql#3033

[fisker]

What if setResponse is like

function setResponse(error) {
  if (error instanceof FooError) {
     throw new BarError()
  }

  if (error instanceof BarError) {
     // ...
  }
}

[dimaMachina]

@fisker possible but very rare case, a perfect case for eslint-disable comment

[fisker]

I'd say this example is also rare case ...

Anyway, if this get accepted, as a reminder, should be carefully when there are flow control statements, including return/break/continue/throw.

[fisker]

Another possible rule proposal in this code.

    try {
+    try {
      // ...
+    } finally {
      setIsFetching(false);
+    }      
-      setSubscription(null);
    } catch (error) {
-      setIsFetching(false);
      setResponse(someAnotherFunction(error));
-      setSubscription(null);
    }
+   finally {
+      setSubscription(null);
+   }

(typing on cellphone, maybe bad indentation)