Struct neon::handle::Handle

source ·
#[repr(transparent)]
pub struct Handle<'a, T: Managed + 'a> { /* private fields */ }
Expand description

A handle to a JavaScript value that is owned by the JavaScript engine.

Implementations§

Safely upcast a handle to a supertype.

This method does not require an execution context because it only copies a handle.

Tests whether this value is an instance of the given type.

Example:
let v: Handle<JsValue> = cx.number(17).upcast();
v.is_a::<JsString, _>(&mut cx); // false
v.is_a::<JsNumber, _>(&mut cx); // true
v.is_a::<JsValue, _>(&mut cx);  // true

Attempts to downcast a handle to another type, which may fail. A failure to downcast does not throw a JavaScript exception, so it’s OK to continue interacting with the JS engine if this method produces an Err result.

Attempts to downcast a handle to another type, raising a JavaScript TypeError exception on failure. This method is a convenient shorthand, equivalent to self.downcast::<U>().or_throw::<C>(cx).

Returns a Region representing a typed region of this buffer, starting at offset and containing len elements of type T.

The region is not checked for validity by this method. Regions are only validated when they are converted to typed arrays.

Example
let buf: Handle<JsArrayBuffer> = cx.argument(0)?;
let region = buf.region::<u32>(64, 8);
println!("offset={}, len={}, size={}", region.offset(), region.len(), region.size());

See the Region documentation for more information.

Trait Implementations§

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
The resulting type after dereferencing.
Dereferences the value.
Mutably dereferences the value.

Creates an Error on error

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.