How to access JS object properties in Wasm (Rust)?

3
votes

I'm using wasm bindgen and I have following function :

#[wasm_bindgen]
pub fn obj(o: &JsValue){
console::log_1(o);
}

and in js I call this function obj({name: "john"}); and it works fine, but when i try to console::log_1(o.name); it gives error unknown field pointing at name

1
rustwebassemblywasm-bindgen
The error with unknown field occurs when compiling or at runtime? - Jonas Bojesen

1 Answers

3
votes

JsValue does not have a field name. To get this field you have to declare the JS object.

Variant 1

Add serde to your dependencies:

serde = "^1.0.101"
serde_derive = "^1.0.101"

Rust code:

extern crate serde;

#[derive(Serialize, Deserialize)]
pub struct User {
    pub name: String,
}

#[wasm_bindgen]
pub fn obj(o: &JsValue){
    let user: User = o.into_serde().unwrap();
    console::log_1(user.name);
}

Variant 2

Another way is to use wasm-bindgen directly but I never used it. It should work like this I think:

#[wasm_bindgen]
pub struct User {
    pub name: String,
}

#[wasm_bindgen]
pub fn obj(o: User){
    console::log_1(o.name);
}