Jul 17, 2026· 6 min read
Add TypeScript to a JavaScript Project
Learn how to add TypeScript to an existing JavaScript project without rewriting everything. Install TypeScript, create a tsconfig, and start getting type safety file by file.
TypeScript
TypeScript
Type-safe JavaScript with TypeScript
187 tutorials
12 of 187 tutorials
Jul 17, 2026· 5 min read
Use allowJs in TypeScript
allowJs lets TypeScript accept .js files as inputs alongside .ts files. Learn how to enable it, when to use it, and how it helps incremental migration.
TypeScript
Jul 17, 2026· 5 min read
Use checkJs in TypeScript
checkJs enables type checking in JavaScript files. Learn how to enable it, what errors it surfaces, and when to use it during migration.
TypeScript
Jul 17, 2026· 7 min read
Migrate JavaScript to TypeScript Step by Step
A practical step-by-step guide to migrating a JavaScript project to TypeScript. Start with compiler setup, add types gradually, and tighten checks over time.
TypeScript
Jul 17, 2026· 6 min read
Type Existing JavaScript Functions
Learn how to add TypeScript type annotations to existing JavaScript functions. Read the function body to infer types, add parameter and return types, and handle tricky patterns.
TypeScript
Jul 17, 2026· 6 min read
Handle Dynamic Values in TypeScript
Learn how to safely type dynamic values from API responses, JSON parsing, user input, and third-party code. Use unknown, type guards, and runtime validation.
TypeScript
Jul 17, 2026· 6 min read
Replace any During TypeScript Migration
A systematic approach to finding and replacing `any` types during JavaScript-to-TypeScript migration. Learn strategies per context and how to tighten types over time.
TypeScript
Jul 17, 2026· 6 min read
Common JavaScript to TypeScript Migration Mistakes
Avoid the most common mistakes when migrating JavaScript to TypeScript. Learn what goes wrong, why it happens, and how to fix each issue during migration.
TypeScript
Jul 17, 2026· 5 min read
Required Utility Type in TypeScript
Required<T> removes the optional modifier from every property in a type, making all fields mandatory. Use it when optional defaults are not enough and you need every field present.
TypeScript
Jul 17, 2026· 6 min read
Omit Utility Type in TypeScript
Omit creates a new type by removing specific properties from an existing type. Use it when it is easier to say what to exclude than what to include.
TypeScript
Jul 17, 2026· 6 min read
Record Utility Type in TypeScript
Record builds an object type where every key has the same value type. Use it for lookup maps, dictionaries, and any object with a known set of keys.
TypeScript
Jul 17, 2026· 5 min read
ReturnType Utility Type in TypeScript
ReturnType<T> extracts the return type of a function type. Use it to capture a function's output type without duplicating the type annotation.
TypeScript