Struct ContextData 

pub struct ContextData<T: Clone>(pub T);

Captures a ContextData data from the Context as a JS function argument, based on its type.

The host defined type must implement Clone, otherwise the borrow checker would not be able to ensure the safety of the context while making the function call. Because of this, it is recommended to use types that are cheap to clone.

For example,

use boa_interop::{ContextData, IntoJsFunctionCopied};

#[derive(Clone, Debug, Finalize, JsData, Trace)]
struct CustomHostDefinedStruct {
    #[unsafe_ignore_trace]
    pub counter: usize,
}
let mut context = Context::default();
context.insert_data(CustomHostDefinedStruct { counter: 123 });
let f = (|ContextData(host): ContextData<CustomHostDefinedStruct>| host.counter + 1)
    .into_js_function_copied(&mut context);

assert_eq!(
    f.call(&JsValue::undefined(), &[], &mut context),
    Ok(JsValue::new(124))
);

Tuple Fields

0: T

Trait Implementations

impl<T: Clone + Clone> Clone for ContextData<T>

fn clone(&self) -> ContextData<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug + Clone> Debug for ContextData<T>

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

Formats the value using the given formatter.

impl<'a, T: NativeObject + Clone> TryFromJsArgument<'a> for ContextData<T>

fn try_from_js_argument( _this: &'a JsValue, rest: &'a [JsValue], context: &mut Context, ) -> JsResult<(Self, &'a [JsValue])>

Try to convert a JS argument into a Rust value, returning the value and the rest of the arguments to be parsed.