Universal and conditional catch blocks with the new when keyword

[aclaymore]

Related threads:

Catch instanceof guards

It would be really nice to be able to write try { // some code } catch (error instanceof MyCustomError) { // handle the error } catch (error instanceof AnotherCustomError) { // handle the other error } instead of the more verbose try { // some code } catch (error) { if (error instanceof MyCustomError) { // handle the error } else if (error instanceof AnotherCustomError) { // handle the other error } else { throw error; } }

[Need Champion] Catch guards

Proposal: GitHub - jeengbe/proposal-catch-guards The document proposes a new syntax for catch clauses with guards for better code readability: try { someFunction(); } catch ErrorA (err) { // Do something } catch ErrorB | ErrorC (err) { // Do another thing } catch { // Do a third thing } finally { // Clean up } The proposal is in need of a champion and a polished changeset to the spec.