Why is this an issue?

A catch clause that only rethrows the caught exception has the same effect as omitting the catch altogether and letting it bubble up automatically.

try {
  doSomething();
} catch (ex) {  // Noncompliant
  throw ex;
}

Such clauses should either be removed or populated with the appropriate logic.

doSomething();

or

try {
  doSomething();
} catch (ex) {
  console.err(ex);
  throw ex;
}

Resources

Documentation

• MDN - try...catch
• MDN - throw