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Show HN: quicktype converts JSON, TypeScript, GraphQL to types in 18 languages

by dvdsgl on 6/1/20, 1:05 PM with 3 comments

  • by dvdsgl on 6/1/20, 1:06 PM

    Hello, HN!

    quicktype generates types and serializers from JSON, JSON Schema, TypeScript, and GraphQL queries, to help you use JSON type-safely in many languages: C#, Go, Rust, Crystal, C++, Objective-C, Java, TypeScript, JavaScript, JavaScript PropTypes, Flow, Swift, Kotlin, Elm, JSON Schema, Ruby, Dart, Python, Pike, and our latest language, Haskell.

    quicktype has some remarkable features that differentiate it from other JSON converters:

    Type inference: quicktype infers optionals, dates, UUIDs, enums, integers, and unions. It also infers maps (versus objects) using a Markov chain.

    Careful naming: quicktype’s naming system creates nice, legal, unique names for types and properties, handling reserved words and tricky corner cases (e.g. `{ “”: “this is legal”, “null”: “so is this”, "1;DROP TABLE users”: “and this" }`).

    Unions for heterogeneous data: JSON data is often heterogenous. quicktype infers this, and creates union types in languages that support them, or synthetic union types in languages that don’t (e.g. try quicktyping `[0, “zero”]` as Swift and Go).

    Type unification. This works across multiple samples, so you can quicktype a directory of API data, for example, and unify types across all responses (e.g. you’ll get just one `Customer` type, even if customer data occurs in many samples). You can also provide multiple samples for the same type for better coverage.

    Marshalling code: In addition to types, quicktype generates functions for marshalling your types to and from JSON.

    Supports dynamic languages: quicktype can add dynamic typechecks for JavaScript, TypeScript, Flow, Python, and Ruby.

    Convenient CLI: Run `quicktype https://blockchain.info/latestblock -o LatestBlock.ts` to quicktype a Bitcoin API in TypeScript.

    Private hosted app: https://app.quicktype.io/ runs quicktype on the client, so servers never see your data (most JSON converters send your JSON to their server)

    Typed input: Feed quicktype TypeScript or JSON Schema instead of JSON for better control over generated types.

    Code quality: quicktype emits clean code