How to check whether a JsObject is JsUint8Array in 0.21

[photino]

In 0.20, we have object.borrow().is_typed_uint8_array(), but the method is removed in 0.21.

[jedel1043]

If you just need to check the type without further processing, you can do object.is::<Uint8Array>(). If you do need to get data from the type, you can either downcast to get a typed JsObject with object.downcast::<Uint8Array>() (if you want to keep the typed JsObject<Uint8Array>) or object.downcast_ref::<Uint8Array> (if you want to temporarily downcast to &Uint8Array).

You can also use the JsUint8Array wrapper if what you're looking for is to call builtin functions from Uint8Array.

[photino]

Thanks!

[photino]

It throws an error:

the trait `boa_engine::Trace` is not implemented for `boa_engine::builtins::typed_array::Uint8Array`

[jedel1043]

Oops, sorry. Forgot that the typed arrays are a bit special. You can basically do the same but with object.downcast::<TypedArray>(), then call ta.kind() to match against the element type, in this case TypedArrayKind::Uint8

[jedel1043]

e.g.

let ta = object.downcast_ref::<TypedArray>();
if ta.kind() == TypedArrayKind::Uint8 {
    // do things with the byte array
}