Practice · 1 of 3

Narrowing Formatter

CHALLENGE

Difficulty: intermediate+25 XP

Write format(value) handling the union string | number | boolean | null | undefined: strings are trimmed then returned, numbers are formatted with exactly 2 decimals, booleans become "yes"/"no", null/undefined become "—".

Press Submit to check your solution.

Back to lesson: Practice: Unions & Narrowing — Practice