Show HN: Generate TypeScript Types from JSON Samples

by jvilk • 10 years ago

5 1 10 years ago

jvilk• 10 years ago

I wrote a library and command line tool that generates TypeScript types for JSON objects from samples. It can also generate "proxy" objects that typecheck JSON objects at runtime, so you can code against JSON services without fear!

The use cases include:

* (Types) Generating quick-and-dirty TypeScript types for a web service or other JSON service you are coding against using response samples in its documentation.

* (Proxies) Ensuring that your code fails reliably when a service returns a JSON object with data that you do not expect. (Otherwise, your code may chug on with an undefined value and fail in a weird place!)

The generated proxies are also useful for non-TypeScript code when compiled to plain ole JavaScript.

To generate types from samples, I adapted the technique used in the F# Data library, which is described in the following paper:

https://dl.acm.org/citation.cfm?id=2908115

Let me know what you think! In addition to the linked demo, the code is on GitHub:

https://github.com/jvilk/maketypes

And there's an NPM package that contains a command line tool:

https://www.npmjs.com/package/maketypes

Show HN: Generate TypeScript Types from JSON Samples

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