Useless Catch (Re-throws Only)

ID

javascript.useless_catch

Severity

low

Remediation Complexity

auto_fix

Remediation Risk

low

Remediation Effort

low

Resource

Code Smell

Language

JavaScript

Tags

code-style, dead-code

Description

Reports catch (e) { throw e; } clauses whose only effect is to re-throw the caught error. The catch adds no behaviour over not having a catch at all — including any sibling finally block, which runs regardless of whether a catch is present.

Rationale

A catch that only rethrows:

  • hides whether the author intended to handle the error (and forgot) or genuinely wanted a no-op,

  • breaks try/catch symmetry — readers expect a catch to add context, retry, log, recover, or suppress,

  • loses the chance to wrap the error with a domain message.

// Bad - catch is a no-op
try {
  doWork();
} catch (err) {
  throw err;
}

// Bad - finally still runs without the catch
try {
  doWork();
} catch (e) {
  throw e;
} finally {
  cleanup();
}

Remediation

Either remove the catch clause entirely, or replace the bare rethrow with a real handler.

// Good - no useless catch
try {
  doWork();
} finally {
  cleanup();
}

// Good - real handler adds context
try {
  doWork();
} catch (err) {
  throw new ApplicationError("doWork failed", { cause: err });
}

References