TypeScript Practice Tests: 600+ MCQs & Interview Prep | 2026

This practice test series is built for developers who want to genuinely master TypeScript — not just memorize syntax, but understand *why* the type system behaves the way it does.

The course includes 6 full-length practice tests, 100 questions each (600 questions total), organized into a deliberate learning path:

1. TypeScript Fundamentals & Basic Type System — variables, interfaces, unions, narrowing, and the type-inference rules every TypeScript developer relies on daily

2. Functions, Classes & Object-Oriented Programming — access modifiers, abstract classes, method overriding, and the design principles behind well-structured TypeScript code

3. Generics & Advanced Types — conditional types, mapped types, template literal types, and the full set of built-in utility types

4. Modules, Declaration Files & Advanced Type System Features — organizing multi-file projects, writing your own .d.ts files, and extending third-party library types

5. Compiler Configuration & Tooling — tsconfig.json options explained with real reasoning, plus ESLint, Prettier, CI integration, and monorepo patterns

6. Ecosystem: React, Node & Testing with TypeScript — typing hooks, Express routes, Jest tests, and the libraries (Zod, Prisma, tRPC) real teams use

Every question includes a detailed explanation for every answer choice — not just the correct one — so you understand exactly why each option is right or wrong. Here's a real example from the course:

Q: Which of the following best describes the `satisfies` operator?

A) It checks that a value's type is compatible with a given type, while preserving the value's own more specific inferred type (unlike a type annotation, which would widen the expression's type). Correct — satisfies validates compatibility while keeping the narrower inferred type.

B) It behaves identically to `as`, performing an unchecked assertion. Incorrect — unlike `as`, satisfies genuinely validates compatibility rather than just forcing the compiler's view.

C) It's used exclusively to validate function parameter counts. Incorrect — it's a general-purpose shape-validation operator, not limited to parameter counts.

D) It converts the value into a Promise. Incorrect — it's a compile-time construct with no runtime transformation.

That's the level of reasoning behind every one of the 600 questions — not just "is this right," but "why is everything else wrong."

Whether you're preparing for a technical interview, ramping up on a new TypeScript codebase, or simply want to close the gaps in your understanding, this series gives you a structured, thorough, and honest way to test yourself.