Struct MaybePromise

pub struct MaybePromise<'js>(/* private fields */);

A type which behaves like a promise but can wrap any javascript value.

This type is usefull when you are unsure if a function will return a promise. You can call finish and turn it into a future like a normal promise. When the value this type us converted isn’t a promise it will behave like an promise which is already resolved, otherwise it will call the right functions on the promise.

Implementations

impl<'js> MaybePromise<'js>

pub fn as_value(&self) -> &Value<'js>

Reference to the inner value

pub fn into_value(self) -> Value<'js>

Convert into the inner value

pub fn from_value(value: Value<'js>) -> Self

Convert into the inner value

pub fn ctx(&self) -> &Ctx<'js>

Returns the Ctx object associated with this value

pub fn state(&self) -> PromiseState

Returns PromiseState::Resolved if the wrapped value isn’t a promise, otherwise calls Promise::state on the promise and returns it’s value.

pub fn result<T: FromJs<'js>>(&self) -> Option<Result<T>>

Returns the value if self isn’t a promise, otherwise calls Promise::result on the promise.

pub fn finish<T: FromJs<'js>>(&self) -> Result<T>

Returns the value if self isn’t a promise, otherwise calls Promise::finish on the promise.

pub fn into_future<T: FromJs<'js>>(self) -> MaybePromiseFuture<'js, T>

Available on crate feature futures only.

Convert self into a future which will return ready if the wrapped value isn’t a promise, otherwise it will handle the promise like the future returned from Promise::into_future.

Trait Implementations

impl<'js> Clone for MaybePromise<'js>

fn clone(&self) -> MaybePromise<'js>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'js> Debug for MaybePromise<'js>

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

Formats the value using the given formatter.

impl<'js> FromJs<'js> for MaybePromise<'js>

fn from_js(_ctx: &Ctx<'js>, value: Value<'js>) -> Result<Self>

impl<'js> Hash for MaybePromise<'js>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<'js> IntoJs<'js> for MaybePromise<'js>

fn into_js(self, _ctx: &Ctx<'js>) -> Result<Value<'js>>

impl<'js> PartialEq for MaybePromise<'js>

fn eq(&self, other: &MaybePromise<'js>) -> bool

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'js> Eq for MaybePromise<'js>

impl<'js> StructuralPartialEq for MaybePromise<'js>