Flow to TypeScript Converter | Migrate FlowType to TS Instantly

🔄 Flow to TypeScript

Convert Flow type definitions to TypeScript interfaces/types.

📝 Input Flow Code:
📤 Output TypeScript:
// TypeScript will appear here...
💡 Example Flow Samples:
📄 Simple Types
Basic type definitions
📦 Exact Types
Exact objects {| |}
🔒 ReadOnly & Arrays
$ReadOnly and Array types

Seamlessly Migrate Your Codebase to TypeScript

As the industry standard moves toward TypeScript, maintaining legacy Flow codebases becomes increasingly difficult. Our Flow to TypeScript converter is designed to handle the heavy lifting of syntax transformation. It intelligently maps Flow-specific types to their TypeScript equivalents, saving you hours of manual refactoring and reducing the risk of human error.

Key Features for Developers

  • Syntax Mapping: Automatically converts Flow’s maybe types (?type) to TypeScript unions (type | null | undefined).

  • Interface Transformation: Translates Flow interfaces and type aliases into valid TypeScript declarations.

  • Utility Type Support: Handles the conversion of Flow utility types like $ReadOnly, $Shape, and $Keys to TS equivalents.

  • React Integration: Full support for transforming Flow-typed React components, including Props and State definitions.

How the Migration Tool Works

  1. Paste Flow Source: Drop your code containing @flow annotations into the editor.

  2. Automated Mapping: The tool identifies Flow-specific patterns and rewrites them using TypeScript syntax.

  3. Review the Diff: Compare the side-by-side output to ensure the type logic remains consistent.

  4. Download .ts/ .tsx: Save your newly converted code and drop it directly into your TypeScript project.

Why Move from Flow to TypeScript?

TypeScript has become the dominant choice for static typing in JavaScript due to its vast ecosystem, superior IDE support, and community backing.

1. Superior Tooling and IDE Support

TypeScript offers unparalleled autocompletion, refactoring tools, and navigation features in editors like VS Code. Migrating from Flow ensures your team benefits from the best developer experience available today.

2. Ecosystem and Library Definitions

Almost every modern JavaScript library comes with built-in TypeScript definitions (d.ts). By converting to TypeScript, you eliminate the friction of managing external library types that Flow often struggles to support.

3. Future-Proofing Your Project

With Flow’s declining adoption outside of Meta, finding documentation and community support is becoming harder. TypeScript is the "future-proof" choice for long-term project maintenance and hiring.

Frequently Asked Questions

How does it handle Flow’s "Maybe" types?

Flow’s ?string is converted to string | null | undefined in TypeScript to ensure that the strict null-checking behavior is preserved during the transition.

Can it handle complex Flow Utility Types?

Yes, our converter maps common Flow utilities like $Diff<A, B> or $Exact<T> to the closest TypeScript logical equivalents (e.g., using Omit or specific interface structures).

Is the conversion 100% automated?

While our tool handles over 90% of syntax changes, some complex Flow logic might require a quick manual review to ensure the TypeScript compiler's strictness settings are satisfied.

Pro Tips for a Successful Migration

  • Fix Flow Errors First: Ensure your code is passing Flow checks before migrating; a clean Flow base results in a much cleaner TypeScript output.

  • Use Strict Mode: After converting, enable strict: true in your tsconfig.json to catch any subtle logic differences that occurred during the move.

  • Incremental Adoption: You don’t have to move your whole project at once. Use this tool to convert one module at a time and use @ts-nocheck where necessary during the transition.