Struct js_sys::WebAssembly::Instance

#[repr(transparent)]pub struct Instance { /* fields omitted */ }

A WebAssembly.Instance object is a stateful, executable instance of a WebAssembly.Module. Instance objects contain all the exported WebAssembly functions that allow calling into WebAssembly code from JavaScript.

MDN documentation

Implementations

impl Instance

pub fn new(module: &Module, imports: &Object) -> Result<Instance, JsValue>

The WebAssembly.Instance() constructor function can be called to synchronously instantiate a given WebAssembly.Module object. However, the primary way to get an Instance is through the asynchronous WebAssembly.instantiateStreaming() function.

MDN documentation

impl Instance

pub fn exports(&self) -> Object

The exports readonly property of the WebAssembly.Instance object prototype returns an object containing as its members all the functions exported from the WebAssembly module instance, to allow them to be accessed and used by JavaScript.

MDN documentation

Methods from Deref<Target = Object>

pub fn constructor(&self) -> Function

The constructor property returns a reference to the Object constructor function that created the instance object.

MDN documentation

pub fn has_own_property(&self, property: &JsValue) -> bool

The hasOwnProperty() method returns a boolean indicating whether the object has the specified property as its own property (as opposed to inheriting it).

MDN documentation

pub fn is_prototype_of(&self, value: &JsValue) -> bool

The isPrototypeOf() method checks if an object exists in another object’s prototype chain.

MDN documentation

pub fn property_is_enumerable(&self, property: &JsValue) -> bool

The propertyIsEnumerable() method returns a Boolean indicating whether the specified property is enumerable.

MDN documentation

pub fn to_locale_string(&self) -> JsString

The toLocaleString() method returns a string representing the object. This method is meant to be overridden by derived objects for locale-specific purposes.

MDN documentation

pub fn to_string(&self) -> JsString

The toString() method returns a string representing the object.

MDN documentation

pub fn value_of(&self) -> Object

The valueOf() method returns the primitive value of the specified object.

MDN documentation

Methods from Deref<Target = JsValue>

pub const NULL: JsValue

pub const UNDEFINED: JsValue

pub const TRUE: JsValue

pub const FALSE: JsValue

pub fn as_f64(&self) -> Option<f64>

Returns the f64 value of this JS value if it’s an instance of a number.

If this JS value is not an instance of a number then this returns None.

pub fn is_string(&self) -> bool

Tests whether this JS value is a JS string.

pub fn as_string(&self) -> Option<String>

If this JS value is a string value, this function copies the JS string value into wasm linear memory, encoded as UTF-8, and returns it as a Rust String.

To avoid the copying and re-encoding, consider the JsString::try_from() function from js-sys instead.

If this JS value is not an instance of a string or if it’s not valid utf-8 then this returns None.

UTF-16 vs UTF-8

JavaScript strings in general are encoded as UTF-16, but Rust strings are encoded as UTF-8. This can cause the Rust string to look a bit different than the JS string sometimes. For more details see the documentation about the str type which contains a few caveats about the encodings.

pub fn as_bool(&self) -> Option<bool>

Returns the bool value of this JS value if it’s an instance of a boolean.

If this JS value is not an instance of a boolean then this returns None.

pub fn is_null(&self) -> bool

Tests whether this JS value is null

pub fn is_undefined(&self) -> bool

Tests whether this JS value is undefined

pub fn is_symbol(&self) -> bool

Tests whether the type of this JS value is symbol

pub fn is_object(&self) -> bool

Tests whether typeof self == "object" && self !== null.

pub fn is_function(&self) -> bool

Tests whether the type of this JS value is function.

pub fn is_truthy(&self) -> bool

Tests whether the value is “truthy”.

pub fn is_falsy(&self) -> bool

Tests whether the value is “falsy”.

Trait Implementations

impl AsRef<Instance> for Instance

fn as_ref(&self) -> &Instance

Performs the conversion.

impl AsRef<JsValue> for Instance

fn as_ref(&self) -> &JsValue

Performs the conversion.

impl AsRef<Object> for Instance

fn as_ref(&self) -> &Object

Performs the conversion.

impl Clone for Instance

fn clone(&self) -> Instance

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Instance

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

Formats the value using the given formatter.

impl Deref for Instance

type Target = Object

The resulting type after dereferencing.

fn deref(&self) -> &Object

Dereferences the value.

impl Eq for Instance

impl From<Instance> for JsValue

fn from(obj: Instance) -> JsValue

Performs the conversion.

impl From<Instance> for Object

fn from(obj: Instance) -> Object

Performs the conversion.

impl From<JsValue> for Instance

fn from(obj: JsValue) -> Instance

Performs the conversion.

impl FromWasmAbi for Instance

type Abi = <JsValue as FromWasmAbi>::Abi

The wasm ABI type that this converts from when coming back out from the ABI boundary.

unsafe fn from_abi(js: Self::Abi) -> Self

Recover a Self from Self::Abi.

impl IntoWasmAbi for Instance

type Abi = <JsValue as IntoWasmAbi>::Abi

The wasm ABI type that this converts into when crossing the ABI boundary.

fn into_abi(self) -> Self::Abi

Convert self into Self::Abi so that it can be sent across the wasm ABI boundary.

impl<'a> IntoWasmAbi for &'a Instance

type Abi = <&'a JsValue as IntoWasmAbi>::Abi

The wasm ABI type that this converts into when crossing the ABI boundary.

fn into_abi(self) -> Self::Abi

Convert self into Self::Abi so that it can be sent across the wasm ABI boundary.

impl JsCast for Instance

fn instanceof(val: &JsValue) -> bool

Performs a dynamic instanceof check to see whether the JsValue provided is an instance of this type.

fn unchecked_from_js(val: JsValue) -> Self

Performs a zero-cost unchecked conversion from a JsValue into an instance of Self

fn unchecked_from_js_ref(val: &JsValue) -> &Self

Performs a zero-cost unchecked conversion from a &JsValue into an instance of &Self.

pub fn has_type<T>(&self) -> bool where
    T: JsCast, 

Test whether this JS value has a type T.

pub fn dyn_into<T>(self) -> Result<T, Self> where
    T: JsCast, 

Performs a dynamic cast (checked at runtime) of this value into the target type T.

pub fn dyn_ref<T>(&self) -> Option<&T> where
    T: JsCast, 

Performs a dynamic cast (checked at runtime) of this value into the target type T.

pub fn unchecked_into<T>(self) -> T where
    T: JsCast, 

Performs a zero-cost unchecked cast into the specified type.

pub fn unchecked_ref<T>(&self) -> &T where
    T: JsCast, 

Performs a zero-cost unchecked cast into a reference to the specified type.

pub fn is_instance_of<T>(&self) -> bool where
    T: JsCast, 

Test whether this JS value is an instance of the type T.

pub fn is_type_of(val: &JsValue) -> bool

Performs a dynamic check to see whether the JsValue provided is a value of this type.

impl OptionFromWasmAbi for Instance

fn is_none(abi: &Self::Abi) -> bool

Tests whether the argument is a “none” instance. If so it will be deserialized as None, and otherwise it will be passed to FromWasmAbi.

impl OptionIntoWasmAbi for Instance

fn none() -> Self::Abi

Returns an ABI instance indicating “none”, which JS will interpret as the None branch of this option.

impl<'a> OptionIntoWasmAbi for &'a Instance

fn none() -> Self::Abi

Returns an ABI instance indicating “none”, which JS will interpret as the None branch of this option.

impl PartialEq<Instance> for Instance

fn eq(&self, other: &Instance) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Instance) -> bool

This method tests for !=.

impl RefFromWasmAbi for Instance

type Abi = <JsValue as RefFromWasmAbi>::Abi

The wasm ABI type references to Self are recovered from.

type Anchor = ManuallyDrop<Instance>

The type that holds the reference to Self for the duration of the invocation of the function that has an &Self parameter. This is required to ensure that the lifetimes don’t persist beyond one function call, and so that they remain anonymous.

unsafe fn ref_from_abi(js: Self::Abi) -> Self::Anchor

Recover a Self::Anchor from Self::Abi.

impl StructuralEq for Instance

impl StructuralPartialEq for Instance

impl WasmDescribe for Instance

fn describe()