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JavaScript & TypeScript

Optional Chaining

/ˈɒpʃənəl ˈtʃeɪnɪŋ/

Definition

The ?. operator that short-circuits and returns undefined instead of throwing when accessing a property of null/undefined.

Example in context

"user?.address?.city returns undefined safely if user or address is null — no TypeError crash."

Related terms

  • Nullish coalescing — The ?? operator that returns the right-hand value only when the left side is null or undefined (not falsy).
  • Type narrowing — TypeScript's ability to refine a variable's type within a conditional block based on type guards or checks.

Practice this term

Master Optional Chaining in context by working through exercises in the JavaScript & TypeScript module. You'll see the term used in real engineering scenarios with multiple-choice, fill-in-the-blank, and matching drills.

Practice in exercises → Browse all words

Frequently Asked Questions

What does "Optional Chaining" mean?

The ?. operator that short-circuits and returns undefined instead of throwing when accessing a property of null/undefined.

How do you pronounce "Optional Chaining"?

"Optional Chaining" is pronounced /ˈɒpʃənəl ˈtʃeɪnɪŋ/.

Can you use "Optional Chaining" in a sentence?

"user?.address?.city returns undefined safely if user or address is null — no TypeError crash."