Trait rquickjs_core::class::ClassDef

source ·

pub trait ClassDef {
    const CLASS_NAME: &'static str;
    const HAS_PROTO: bool = false;
    const HAS_STATIC: bool = false;
    const HAS_REFS: bool = false;

    // Required method
    fn class_id() -> &'static ClassId;

    // Provided methods
    fn init_proto<'js>(_ctx: Ctx<'js>, _proto: &Object<'js>) -> Result<()> { ... }
    fn init_static<'js>(_ctx: Ctx<'js>, _static: &Object<'js>) -> Result<()> { ... }
    fn mark_refs(&self, _marker: &RefsMarker) { ... }
    fn into_js_obj<'js>(self, ctx: Ctx<'js>) -> Result<Value<'js>>
       where Self: Sized { ... }
    fn from_js_ref<'js>(ctx: Ctx<'js>, value: Value<'js>) -> Result<&'js Self>
       where Self: Sized { ... }
    fn from_js_obj<'js>(ctx: Ctx<'js>, value: Value<'js>) -> Result<Self>
       where Self: Clone + Sized { ... }
}

Available on crate feature classes only.

Expand description

The ES6 class definition trait

This trait helps export rust data types to QuickJS so JS code can interoperate with it as with usual ES6 classes. Usually implementing this trait only is not enough to introduce class. At least IntoJs trait should be implemented for transfering class instances to JS side. Get be able call methods or get access to class properties the FromJs trait should be implemented for class reference and for mutable reference when needed.

NOTE: Usually no need implements this trait manually. Instead you can use class_def macro or bind attribute to export classes to JS in easy way.

#[derive(Clone)]
struct MyClass;

impl ClassDef for MyClass {
    const CLASS_NAME: &'static str = "MyClass";

    fn class_id() -> &'static ClassId {
        static CLASS_ID: ClassId = ClassId::new();
        &CLASS_ID
    }

    // With prototype
    const HAS_PROTO: bool = true;
    fn init_proto<'js>(ctx: Ctx<'js>, proto: &Object<'js>) -> Result<()> {
        Ok(())
    }

    // With statics
    const HAS_STATIC: bool = true;
    fn init_static<'js>(ctx: Ctx<'js>, ctor: &Object<'js>) -> Result<()> {
        Ok(())
    }

    // With internal references
    const HAS_REFS: bool = true;
    fn mark_refs(&self, marker: &RefsMarker) {
        // marker.mark(&self.some_persistent_value);
    }
}

impl<'js> IntoJs<'js> for MyClass {
    fn into_js(self, ctx: Ctx<'js>) -> Result<Value<'js>> {
        self.into_js_obj(ctx)
    }
}

impl<'js> FromJs<'js> for &'js MyClass {
    fn from_js(ctx: Ctx<'js>, value: Value<'js>) -> Result<Self> {
        MyClass::from_js_ref(ctx, value)
    }
}

impl<'js> FromJs<'js> for MyClass {
    fn from_js(ctx: Ctx<'js>, value: Value<'js>) -> Result<Self> {
        MyClass::from_js_obj(ctx, value)
    }
}