Struct js_sys::AsyncIterator

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#[repr(transparent)]
pub struct AsyncIterator { /* private fields */ }
Expand description

Any object that conforms to the JS async iterator protocol. For example, something returned by myObject[Symbol.asyncIterator]().

MDN documentation

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impl AsyncIterator

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pub fn next(&self) -> Result<Promise, JsValue>

The next() method always has to return a Promise which resolves to an object with appropriate properties including done and value. If a non-object value gets returned (such as false or undefined), a TypeError (“iterator.next() returned a non-object value”) will be thrown.

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pub const NULL: JsValue = JsValue{ idx: JSIDX_NULL, _marker: marker::PhantomData,}

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pub const UNDEFINED: JsValue = JsValue{ idx: JSIDX_UNDEFINED, _marker: marker::PhantomData,}

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pub const TRUE: JsValue = JsValue{ idx: JSIDX_TRUE, _marker: marker::PhantomData,}

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pub const FALSE: JsValue = JsValue{ idx: JSIDX_FALSE, _marker: marker::PhantomData,}

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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.

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pub fn is_string(&self) -> bool

Tests whether this JS value is a JS string.

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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.

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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.

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pub fn is_null(&self) -> bool

Tests whether this JS value is null

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pub fn is_undefined(&self) -> bool

Tests whether this JS value is undefined

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pub fn is_symbol(&self) -> bool

Tests whether the type of this JS value is symbol

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pub fn is_object(&self) -> bool

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

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pub fn is_array(&self) -> bool

Tests whether this JS value is an instance of Array.

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pub fn is_function(&self) -> bool

Tests whether the type of this JS value is function.

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pub fn is_bigint(&self) -> bool

Tests whether the type of this JS value is bigint.

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pub fn js_typeof(&self) -> JsValue

Applies the unary typeof JS operator on a JsValue.

MDN documentation

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pub fn js_in(&self, obj: &JsValue) -> bool

Applies the binary in JS operator on the two JsValues.

MDN documentation

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pub fn is_truthy(&self) -> bool

Tests whether the value is “truthy”.

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pub fn is_falsy(&self) -> bool

Tests whether the value is “falsy”.

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pub fn loose_eq(&self, other: &JsValue) -> bool

Compare two JsValues for equality, using the == operator in JS.

MDN documentation

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pub fn bit_not(&self) -> JsValue

Applies the unary ~ JS operator on a JsValue.

MDN documentation

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pub fn unsigned_shr(&self, rhs: &JsValue) -> u32

Applies the binary >>> JS operator on the two JsValues.

MDN documentation

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pub fn checked_div(&self, rhs: &JsValue) -> JsValue

Applies the binary / JS operator on two JsValues, catching and returning any RangeError thrown.

MDN documentation

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pub fn pow(&self, rhs: &JsValue) -> JsValue

Applies the binary ** JS operator on the two JsValues.

MDN documentation

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pub fn lt(&self, other: &JsValue) -> bool

Applies the binary < JS operator on the two JsValues.

MDN documentation

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pub fn le(&self, other: &JsValue) -> bool

Applies the binary <= JS operator on the two JsValues.

MDN documentation

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pub fn ge(&self, other: &JsValue) -> bool

Applies the binary >= JS operator on the two JsValues.

MDN documentation

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pub fn gt(&self, other: &JsValue) -> bool

Applies the binary > JS operator on the two JsValues.

MDN documentation

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pub fn unchecked_into_f64(&self) -> f64

Applies the unary + JS operator on a JsValue. Can throw.

MDN documentation

Trait Implementations§

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impl AsRef<AsyncIterator> for AsyncIterator

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fn as_ref(&self) -> &AsyncIterator

Converts this type into a shared reference of the (usually inferred) input type.
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impl AsRef<JsValue> for AsyncIterator

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fn as_ref(&self) -> &JsValue

Converts this type into a shared reference of the (usually inferred) input type.
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impl Clone for AsyncIterator

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fn clone(&self) -> AsyncIterator

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for AsyncIterator

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

Formats the value using the given formatter. Read more
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impl Deref for AsyncIterator

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type Target = JsValue

The resulting type after dereferencing.
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fn deref(&self) -> &JsValue

Dereferences the value.
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impl From<AsyncIterator> for JsValue

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fn from(obj: AsyncIterator) -> JsValue

Converts to this type from the input type.
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impl From<JsValue> for AsyncIterator

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fn from(obj: JsValue) -> AsyncIterator

Converts to this type from the input type.
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impl FromWasmAbi for AsyncIterator

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type Abi = <JsValue as FromWasmAbi>::Abi

The wasm ABI type that this converts from when coming back out from the ABI boundary.
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unsafe fn from_abi(js: Self::Abi) -> Self

Recover a Self from Self::Abi. Read more
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impl<'a> IntoWasmAbi for &'a AsyncIterator

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

The wasm ABI type that this converts into when crossing the ABI boundary.
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fn into_abi(self) -> Self::Abi

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

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type Abi = <JsValue as IntoWasmAbi>::Abi

The wasm ABI type that this converts into when crossing the ABI boundary.
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fn into_abi(self) -> Self::Abi

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

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fn instanceof(val: &JsValue) -> bool

Performs a dynamic instanceof check to see whether the JsValue provided is an instance of this type. Read more
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fn is_type_of(val: &JsValue) -> bool

Performs a dynamic check to see whether the JsValue provided is a value of this type. Read more
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fn unchecked_from_js(val: JsValue) -> Self

Performs a zero-cost unchecked conversion from a JsValue into an instance of Self Read more
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fn unchecked_from_js_ref(val: &JsValue) -> &Self

Performs a zero-cost unchecked conversion from a &JsValue into an instance of &Self. Read more
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fn has_type<T>(&self) -> boolwhere T: JsCast,

Test whether this JS value has a type T. Read more
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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. Read more
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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. Read more
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fn unchecked_into<T>(self) -> Twhere T: JsCast,

Performs a zero-cost unchecked cast into the specified type. Read more
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fn unchecked_ref<T>(&self) -> &Twhere T: JsCast,

Performs a zero-cost unchecked cast into a reference to the specified type. Read more
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fn is_instance_of<T>(&self) -> boolwhere T: JsCast,

Test whether this JS value is an instance of the type T. Read more
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impl LongRefFromWasmAbi for AsyncIterator

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type Abi = <JsValue as LongRefFromWasmAbi>::Abi

Same as RefFromWasmAbi::Abi
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type Anchor = AsyncIterator

Same as RefFromWasmAbi::Anchor
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unsafe fn long_ref_from_abi(js: Self::Abi) -> Self::Anchor

Same as RefFromWasmAbi::ref_from_abi
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impl OptionFromWasmAbi for AsyncIterator

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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.
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impl<'a> OptionIntoWasmAbi for &'a AsyncIterator

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fn none() -> Self::Abi

Returns an ABI instance indicating “none”, which JS will interpret as the None branch of this option. Read more
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impl OptionIntoWasmAbi for AsyncIterator

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fn none() -> Self::Abi

Returns an ABI instance indicating “none”, which JS will interpret as the None branch of this option. Read more
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impl RefFromWasmAbi for AsyncIterator

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type Abi = <JsValue as RefFromWasmAbi>::Abi

The wasm ABI type references to Self are recovered from.
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type Anchor = ManuallyDrop<AsyncIterator>

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

Recover a Self::Anchor from Self::Abi. Read more
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impl WasmDescribe for AsyncIterator

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

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fn into(self) -> U

Calls U::from(self).

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

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impl<T> ReturnWasmAbi for Twhere T: IntoWasmAbi,

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type Abi = <T as IntoWasmAbi>::Abi

Same as IntoWasmAbi::Abi
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fn return_abi(self) -> <T as ReturnWasmAbi>::Abi

Same as IntoWasmAbi::into_abi, except that it may throw and never return in the case of Err.
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impl<T> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.