Migrating from C# to TypeScript: A Developer's Guide

C# and TypeScript are both languages with strong static typing features. However, when migrating from one to the other, it's crucial to understand some key differences to write clean and idiomatic code. In this guide, we'll cover the TypeScript equivalents of common C# constructs—such as classes, records, enums, and collections—and provide practical methods to ease the migration process.

Mapping Data Structures

C# classes often map to **interfaces** or **types** in TypeScript. C# `record` types can be translated into concise TypeScript types. For enums, while TypeScript supports both numeric and string enums, using **string union types** (e.g., 'Active' | 'Passive') is often preferred for a better developer experience as it catches invalid value assignments at compile time.

Nullability and Collections

C#'s **nullable reference types** can be represented in TypeScript using **| null** or **| undefined** union types. To denote an optional field, use the **?:** operator. C# collection types like `IEnumerable` and `List` typically map to **T[]** arrays in TypeScript. For dictionary types, you can use types like **Record**.

Tools to Facilitate Migration

You can leverage various tools to speed up the migration process. Use the JSON to TypeScript generator to automatically create TypeScript interfaces from your existing API responses. If you want to translate your C# class models directly, the C# to TypeScript converter can provide a quick starting point. To ensure your changes are safe, use the JSON Diff tool to compare API payloads and catch structural differences early.

Additional Notes

Remember that concepts specific to C#, such as namespaces and access modifiers, have different paradigms in TypeScript. By using TypeScript's modules (ESM) and a file-based structure, you can better organize your code for front-end consumption.