Question 1

How do I convert JSON to TypeScript type?

Accepted Answer

Paste JSON into generator. Tool analyzes structure. Infers TypeScript types from values: string, number, boolean, arrays, nested objects. Generates interface definitions. Copy TypeScript code to your project. Use for API responses, config files, database models. Manual: define interface matching JSON structure.

Question 2

What is the difference between interface and type in TypeScript?

Accepted Answer

Interface: defines object shape, can be extended/merged, preferred for objects. Type: defines any type including primitives, unions, intersections, more flexible. Use interface for object definitions. Use type for unions, primitives, computed types. Both work for objects - choose based on project convention. Interface can be declaration-merged.

Question 3

How do I handle nested JSON objects in TypeScript?

Accepted Answer

Generator creates nested interfaces for nested objects. Each nested object gets its own interface with capitalized key name. Top-level interface references nested interfaces. Example: {user: {profile: {...}}} generates User interface and Profile interface. Keep interfaces flat or nest based on preference. Use dot notation for deep access.

Question 4

How do I type arrays in TypeScript?

Accepted Answer

Array syntax: Type[] or Array<Type>. Example: string[] for string arrays. Mixed arrays: (string | number)[] union. Array of objects: MyObject[] where MyObject is interface. Tuple: [string, number] fixed length and types. Readonly arrays: readonly Type[]. Generator infers array types from first element or unions from mixed elements.

Question 5

How do I use TypeScript types for API responses?

Accepted Answer

Generate type from sample API response. Copy interface to your project. Use fetch/axios with typed response: fetch(url).then(res => res.json() as MyResponse). Or use generic: axios.get<MyResponse>(url). TypeScript validates response shape. Catch type errors at compile time. Document API types with generated definitions.

TypeScript Type Generator

Input JSON

Generated TypeScript

TypeScript Types Reference

Use Cases