Interview Q&A / TypeScript

1. Should you use an enum or a union of string literals in TypeScript?

   Both describe a fixed set of allowed values. An enum creates a real JavaScript object at runtime and its members must be referenced by name. A union of string literals like "admin" | "user" exists only at compile time, adds no code, and accepts plain strings. Many teams now prefer unions, or an as const object when they also need runtime values.

   IntermediateIn-depth4 min read
2. What is type narrowing in TypeScript, and how do type guards work?

   Narrowing is how TypeScript refines a broad type, like string | number, to a more specific one inside a block after a check. Type guards are those checks, such as typeof, instanceof, the in operator, equality checks on a shared field, and custom functions that return a type predicate like value is User.

   IntermediateIn-depth3 min read