Format TypeScript Online Free — Prettier for TypeScript in Your Browser

TypeScript formatting is identical to JavaScript formatting in most cases — Prettier handles both with the same engine. The key difference is that the TypeScript parser understands type annotations, interfaces, generics, decorators, and other TS-specific syntax, so it formats them correctly without treating them as errors.

This page explains how to use our free online formatter to format TypeScript code, which TS constructs are handled, and when to use browser formatting vs a local setup.

TypeScript Formatting vs JavaScript Formatting

When you select TypeScript in the formatter, it uses Prettier's TypeScript parser instead of the JavaScript parser. The practical differences:

• Type annotations — : string, : number[], : Record<string, unknown> are formatted without errors
• Interfaces and type aliases — interface Foo and type Bar = ... blocks are formatted correctly
• Generics — Array<T>, Promise<void>, complex generic constraints all work
• Decorators — @Injectable(), @Component() are handled by the TS parser
• Enums — enum Direction { Up, Down } are formatted properly
• Non-null assertions — the ! operator is preserved

All standard JavaScript formatting options (tab width, quotes, semicolons, trailing commas) apply the same way to TypeScript.

When TypeScript Formatting Is Most Useful

The browser formatter is most helpful in these TypeScript scenarios:

• Copying code from Stack Overflow or documentation — code examples are often collapsed or inconsistently indented
• Reviewing code in a PR without VS Code — format it first to see the structure clearly
• Working on a machine without the project set up — format without installing node_modules
• Sharing code in documentation or blog posts — paste formatted TypeScript into Notion, Confluence, or markdown files
• Quick reformatting before a code review — clean up your own code before asking for review

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Does It Format TypeScript + React (TSX)?

Select "TypeScript" in the language dropdown and paste TSX code — Prettier's TypeScript parser handles JSX syntax inside TypeScript files. React component code with type props, hooks, and JSX all format correctly.

For example:

interface Props { name: string; onClick: () => void } combined with JSX return blocks will format cleanly as TSX.

Matching Your Project's Prettier Config

If your TypeScript project has a .prettierrc file, match those settings in the formatter options:

• Semi: check if your project uses "semi": false
• Quotes: check "singleQuote": true vs default double
• Tab width: 2 vs 4 (2 is standard for TypeScript/Angular projects)
• Trailing commas: check "trailingComma": "all" vs "es5"

With the right settings, the output from this browser formatter is byte-for-byte identical to what prettier --write would produce locally.

Frequently Asked Questions

Does it support all TypeScript versions?

Yes. Prettier's TypeScript parser handles all TypeScript syntax up to the latest version, including newer features like const type parameters and variadic tuple types.

Can it format .d.ts declaration files?

Yes. Declaration files are valid TypeScript and format correctly with the TypeScript parser.

Will it catch TypeScript type errors?

No. Formatting only changes whitespace and structure. Type checking requires the TypeScript compiler (tsc). Use your IDE or the TypeScript compiler for type errors.

What if I have Vue or Svelte TypeScript files?

This formatter handles plain .ts and .tsx files. Vue SFCs (.vue) and Svelte (.svelte) have their own Prettier plugins that require local setup.