JavaScript to TypeScript Converter - Convert JS to TS Online
Free online tool to convert JavaScript code to TypeScript with automatic type inference and interface generation.
JavaScript to TypeScript Converter
Convert JavaScript code to TypeScript with type annotations
JavaScript Input
TypeScript Output
TypeScript code will appear here
Paste JavaScript in the input area
How to Convert JavaScript to TypeScript - Step by Step Guide
Input Your JavaScript Code
Let's convert your JavaScript to TypeScript! You have several options:
Example: JavaScript Input
Here's JavaScript code before conversion:
function greet(name) { return "Hello, " + name; }
Automatic Type Inference
The converter analyzes your code and adds TypeScript types:
Example: TypeScript Output
The same code with TypeScript types:
function greet(name: string): string { return "Hello, " + name; }
Review Generated Types
Check and refine the automatically generated TypeScript code:
Export TypeScript Code
Save your converted TypeScript code:
Frequently Asked Questions
Can this tool convert JavaScript to TypeScript automatically?
Yes, the tool analyzes your JavaScript code and automatically adds TypeScript type annotations based on usage patterns. However, complex types may require manual review and adjustment for optimal type safety.
Will the converted TypeScript code work immediately?
The converted code will work with TypeScript compiler in most cases. However, you may need to refine some types, add missing imports, or adjust generic types for complex scenarios. Always test the converted code in your project.
What types does the converter infer?
The converter infers basic types like string, number, boolean, arrays, and objects. It analyzes function parameters and return values to suggest appropriate types. Complex types like unions, generics, and advanced TypeScript features may need manual addition.
Should I convert all JavaScript files to TypeScript?
Converting to TypeScript provides better type safety, improved IDE support, and catches errors at compile time. It's beneficial for large projects and team collaboration. Start with core modules and gradually convert other files.
Can I convert TypeScript back to JavaScript?
Yes, TypeScript compiles to JavaScript. You can use the TypeScript compiler (tsc) to transpile TypeScript back to JavaScript, though you'll lose the type annotations. This is commonly done for browser deployment.
Is the JavaScript to TypeScript converter completely free?
Yes, totally free with no limitations on file size or usage frequency. No registration required, and you can convert unlimited JavaScript files to TypeScript with automatic type inference.