Struct Configuration 

pub struct Configuration { /* private fields */ }

Configuration for runtime-aware TypeScript type remapping.

By default this contains a set of default rules as defined on the module. If you don’t want them use Configuration::empty() instead.

You can add your own rules via Configuration::define(...).

Implementations

impl Configuration

pub fn empty() -> Self

Construct a Configuration without the default rules.

Prefer Configuration::default when possible; the default rules cover common ecosystem types and may grow over time.

pub fn rules_mut(&mut self) -> &mut Vec<Rule>

Exposes the rules applies to this instance for manual manipulation.

This could be used to filter the default rules if you want to exclude certain ones.

pub fn define<T: Type>( self, dt: impl Fn(DataType) -> DataType + Send + Sync + 'static, serialize: Option<Transform>, deserialize: Option<Transform>, ) -> Self

Define a new rule for a given type T.

dt receives the original DataType for T and must return the TypeScript-facing DataType that should replace it. serialize transforms TypeScript runtime values before sending them to Rust. deserialize transforms values received from Rust into TypeScript runtime values.

This only works for named types, such as types generated by the Type derive macro. It does not work for primitives.

use specta::Type;
use specta_typescript::{define, semantic::{Configuration, Transform}};

#[derive(Type)]
struct MyCustomUrl(String);

let mut semantic_types = Configuration::empty();
semantic_types.define::<MyCustomUrl>(
    |_| define("URL").into(), // Runtime Specta Type
    Some(Transform::new(|value| format!("{value}.toString()"))), // JS -> JSON
    Some(Transform::new(|value| format!("new URL({value})"))), // JSON -> JS
);

pub fn enable_lossless_bigints(self) -> Self

Enable lossless support for large integer types (BigInts).

This remaps usize, isize, u64, i64, u128, and i128 so they are a BigInt in JavaScript.

This is only safe if your serialization and deserialization layer can losslessly transmit BigInts to the frontend.

Refer to specta-rs/specta#203 for implementation details.

pub fn enable_lossless_floats(self) -> Self

Enable lossless float support.

By enabling this, you assert that your runtime must preserve NaN, Infinity, and -Infinity values from JavaScript to Rust and we will flatten number | null into number.

Refer to specta-rs/specta#203 for implementation details.

pub fn apply_types<'a>(&self, types: &'a Types) -> Cow<'a, Types>

Transform a Types collection using the configured rules.

This rewrites registered named types so their exported TypeScript shapes match the values produced or consumed by the runtime transforms.

Call this after any format-specific mapping that changes the type graph, and before exporting the final TypeScript definitions.

pub fn apply_serialize( &self, types: &Types, dt: &DataType, js_ident: &str, ) -> Option<(Option<DataType>, String)>

Scan a DataType tree applying serialize-facing rules.

This assumes Configuration::apply_types has already been applied to the Types. Therefore the type updates will be shallow (up until references to the Types).

The returned JavaScript expression is built around js_ident and may be deeply nested for structs, tuples, lists, nullable values, and intersections.

If no rule or built-in remap matches, None is returned. If a rule matches but the type shape does not need to change, Some((None, runtime_str)) is returned.

pub fn apply_deserialize( &self, types: &Types, dt: &DataType, js_ident: &str, ) -> Option<(Option<DataType>, String)>

Scan a DataType tree applying deserialize-facing rules.

Use this for values received from Rust before exposing them to TypeScript callers.

Trait Implementations

impl Clone for Configuration

fn clone(&self) -> Configuration

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Configuration

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Configuration

fn default() -> Self

Returns the “default value” for a type.