Custom Error Types — JS Technical Interview Questions & Answers

Extending Error for domain-specific error classes.

Custom Error Types

  • Custom Error Types (js errors) is a JS topic. In plain words you use it for a short Custom Error Types js errors example in a script in the browser. Don’t start with a slogan — start with that picture.
  • Smallest example: the smallest Custom Error Types js errors example you can type. Type it, run it, and say what you see. If you can do that from memory, you know Custom Error Types (js errors).
  • From the example next to this theory: Extending Error for domain-specific error classes.
  • Trap: only saying “Custom Error Types js errors” with no example. Fix that before you talk about advanced JS.
  • Viva: what is Custom Error Types (js errors)? Then show the smallest Custom Error Types js errors example you can type. Then name the trap.

Technical Interview Tip: What is Custom Error Types (js errors)? Show this: the smallest Custom Error Types js errors example you can type. Trap: only saying “Custom Error Types js errors” with no example.

Code Examples for Custom Error Types

Custom Error Types — working example

function parseAge(raw) {
  const n = Number(raw);
  if (Number.isNaN(n)) throw new TypeError("age must be a number");
  if (n < 0) throw new RangeError("age must be >= 0");
  return n;
}
try {
  console.log(parseAge("21"));
  console.log(parseAge("nope"));
} catch (err) {
  console.log(err.name + ": " + err.message);
} finally {
  console.log("done");
}

Custom Error Types — try/catch handles thrown errors; use Error subtypes for clearer failures; finally always runs.

How to Explain Custom Error Types to an Interviewer

What is Custom Error Types (js errors)?

Used for a short Custom Error Types js errors example a script in the browser Not just the heading

Give one small example of Custom Error Types (js errors).

the smallest Custom Error Types js errors example you can type Extending Error for domain-specific error classes

What mistake do beginners make with Custom Error Types (js errors)?

only saying “Custom Error Types js errors” with no example Show the fix

Where do you use Custom Error Types (js errors)?

a script in the browser a short Custom Error Types js errors example