1 unstable release
0.1.0 | Oct 6, 2022 |
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#10 in #duck
Used in wasm_bindgen_duck_type
4KB
63 lines
wasm_bindgen_duck_type
Macro to automatically generate duck type interfaces with wasm_bindgen
Why
For most cases, Serde should be used to serialize and deserialize objects passed between JavaScript and Rust. Additionally, if the JavaScript object is an instance of a class, this crate is not necessary, as the implementation of the class can be used.
However, some types, such as a web_sys::Element or js_sys::Function, cannot be serialized as text, so this approach will not work. In these cases, this macro can be used to provide a typed interface for interaction, when the JavaScript object is untyped.
How
This crate generates a Duck Typed interface based on the given struct definition, as well as a new
constructor and Default
trait implementation.
Usage
The [wasm_bindgen_duck_type]
attribute macro can be applied to structs to generate the duck type interface for the struct.
Example
JavaScript:
function MyFun() {
return {
number: 20,
fun: () => {
console.log("Hello, World!")
}
};
}
function GetNumber(input) {
return input.number
}
Rust:
use wasm_bindgen_duck_type::wasm_bindgen_duck_type;
use wasm_bindgen::prelude::*;
#[wasm_bindgen]
extern "C" {
fn MyFun() -> MyType;
fn GetNumber(input: MyType) -> i32;
}
#[wasm_bindgen_duck_type]
struct MyType {
number: i32,
fun: js_sys::Function,
}
fn main() {
let result = MyFun();
result.fun().call0(&JsValue::NULL);
result.set_number(10);
let input = MyType::default(); // All fields are null / default
let input = MyType::new(
42,
JsValue::NULL.into() // Pass a function
);
let num = GetNumber(input); // 42
}
lib.rs
:
Implementation for wasm_bindgen_duck_type
Dependencies
~1.5MB
~35K SLoC