Trait wasm_bindgen::convert::WasmAbi

source ·

pub trait WasmAbi {
    type Prim1: WasmPrimitive;
    type Prim2: WasmPrimitive;
    type Prim3: WasmPrimitive;
    type Prim4: WasmPrimitive;

    // Required methods
    fn split(self) -> (Self::Prim1, Self::Prim2, Self::Prim3, Self::Prim4);
    fn join(
        prim1: Self::Prim1,
        prim2: Self::Prim2,
        prim3: Self::Prim3,
        prim4: Self::Prim4,
    ) -> Self;
}

Expand description

A trait which represents types that can be passed across the Wasm ABI boundary, by being split into multiple Wasm primitive types.

Up to 4 primitives are supported; if you don’t want to use all of them, you can set the rest to (), which will cause them to be ignored.

You need to be careful how many primitives you use, however: Result<T, JsValue> uses up 2 primitives to store the error, and so it doesn’t work if T uses more than 2 primitives.

So, if you’re adding support for a type that needs 3 or more primitives and is able to be returned, you have to add another primitive here.

There’s already one type that uses 3 primitives: &mut [T]. However, it can’t be returned anyway, so it doesn’t matter that Result<&mut [T], JsValue> wouldn’t work.

§⚠️ Unstable

This is part of the internal convert module, no stability guarantees are provided. Use at your own risk. See its documentation for more details.