Prefer Type Guards To Unguarded Casts In Catch Blocks

Prefer:


try {
  // Some code that might throw
} catch (error: unknown) {
  if (isExpectedError(error)) {
    // Handle the expected error
  } else {
    // Handle the unexpected error
  }
}

Instead of:


try {
  // Some code that might throw
} catch (error: unknown) {
  const expectedError = error as ExpectedError
  // Handle the expected error
}

Rationale

If something other than an ExpectedError were to be caught, referencing properties on the the unguarded cast of expectedError might cause an additional error in the catch block that would complicate diagnosing the issue.