Crate specta

Easily export your Rust types to other languages

Specta provides a system for type introspection and a set of language exporters which allow you to export your Rust types to other languages!

Currently we only support exporting to TypeScript but work has begun on other languages.

Features

• Export structs and enums to Typescript
• Get function types to use in libraries like tauri-specta
• Supports wide range of common crates in Rust ecosystem
• Supports type inference - can determine type of fn demo() -> impl Type.

Ecosystem

Specta can be used in your application either directly or through a library which simplifies the process of using it.

• rspc for easily building end-to-end typesafe APIs
• tauri-specta for typesafe Tauri commands

Example

use specta::{*, ts::*};

#[derive(Type)]
pub struct MyCustomType {
   pub my_field: String,
}

fn main() {
    assert_eq!(
        ts::export::<MyCustomType>(&ExportConfig::default()).unwrap(),
        "export type MyCustomType = { my_field: string }".to_string()
    );
}

Supported Libraries

If you are using Prisma Client Rust you can enable the rspc feature on it to allow for Specta support on types coming directly from your database. This includes support for the types created via a selection.

Feature flags

• function - Support for exporting the types of Rust functions.
• export - Support for collecting up a global type map

Languages

• typescript - Support for TypeScript language exporting
• js_doc - Support for JSDoc exporting helpers. Also requires typescript feature to be enabled.

Compatability

• serde - Support for serde
• serde_json - Support for serde-json
• serde_yaml - Support for serde_yaml
• toml - Support for toml
• tauri - Support for Tauri. This is required when using specta::function with Tauri Commands.

External types

• ulid - ulid crate
• uuid - uuid crate
• chrono - chrono crate
• time - time crate
• bigdecimal - bigdecimal crate
• rust_decimal - rust_decimal crate
• indexmap - indexmap crate
• ipnetwork - ipnetwork crate
• mac_address - mac_address crate
• bit-vec - bit-vec crate
• bson - bson crate
• uhlc - uhlc crate
• bytesize - bytesize crate
• glam - glam crate
• tokio - tokio crate
• url - url crate
• either - either crate
• bevy_ecs - bevy_ecs crate

Alternatives

Why not ts-rs?

ts-rs is a great library, but it has a few limitations which became a problem when I was building rspc. Namely it deals with types individually which means it is not possible to export a type and all of the other types it depends on.

Why not Typeshare?

Typeshare is also great, but its approach is fundamentally different. While Specta uses traits and runtime information, Typeshare statically analyzes your Rust files. This results in a loss of information and lack of compatability with types from other crates.

Modules

• datatype
  Types related to working with DataType. Exposed for advanced users.
• functionfunction
  Support for exporting Rust function.

Structs

• ImplLocation
  The location of the impl block for a given type. This is used for error reporting. The content of it is transparent and is generated by the macros.
• SpectaID
  The unique Specta ID for the type.
• TypeMap
  A map used to store the types “discovered” while exporting a type.

Enums

• Generics
  TODO

Traits

• Flatten
  A marker trait for compile-time validation of which types can be flattened.
• Language
  TODO
• NamedType
  represents a type that can be converted into NamedDataType. This will be implemented for all types with the Type derive macro.
• Type
  Provides runtime type information that can be fed into a language exporter to generate a type definition in another language. Avoid implementing this trait yourself where possible and use the Type macro instead.

Attribute Macros

• spectaderive and function
  Prepares a function to have its types extracted using functions::fn_datatype

Derive Macros

• Typederive
  Implements Type for a given struct or enum.