Struct Promise 

pub struct Promise<'p> {
    promise: Local<'p, *mut JSObject>,
}

Represents a Promise in the JavaScript Runtime. Refer to MDN for more details.

Fields

promise: Local<'p, *mut JSObject>

Implementations

impl<'p> Promise<'p>

pub fn new(cx: &'p Context) -> Promise<'p>

Creates a new Promise which never resolves.

pub fn with_executor<F>(cx: &'p Context, executor: F) -> Option<Promise<'p>>

where F: for<'cx> FnOnce(&'cx Context, Function<'cx>, Function<'cx>) -> Result<()> + 'static,

Creates a new Promise with an executor. The executor is a function that takes in two functions, resolve and reject. resolve and reject can be called with a Value to resolve or reject the promise with the given value.

pub fn block_on_future<F, Output, Error>( cx: &'p Context, future: F, ) -> Option<Promise<'p>>

where F: Future<Output = Result<Output, Error>> + 'static, Output: for<'cx> ToValue<'cx> + 'static, Error: for<'cx> ToValue<'cx> + 'static,

Creates a new Promise with a Future. The future is run to completion on the current thread and cannot interact with an asynchronous runtime.

The Result of the future determines if the promise is resolved or rejected.

pub fn resolved(cx: &'p Context, value: &Value<'_>) -> Promise<'p>

Creates a new Promise, that is resolved to the given value. Similar to Promise.resolve

pub fn rejected(cx: &'p Context, value: &Value<'_>) -> Promise<'p>

Creates a new Promise, that is rejected to the given value. Similar to Promise.reject

pub fn from(object: Local<'p, *mut JSObject>) -> Option<Promise<'p>>

Creates a Promise from an object.

pub unsafe fn from_unchecked(object: Local<'p, *mut JSObject>) -> Promise<'p>

Creates a Promise from aj object

Safety

Object must be a Promise.

pub fn id(&self) -> u64

Returns the ID of the Promise.

pub fn state(&self) -> PromiseState

Returns the state of the Promise.

The state can be Pending, Fulfilled and Rejected.

pub fn result<'cx>(&self, cx: &'cx Context) -> Value<'cx>

Returns the result of the Promise.

pub fn add_reactions<'cx, T, C>( &self, cx: &'cx Context, on_resolved: T, on_rejected: C, ) -> bool

where T: for<'cx2> FnOnce(&'cx2 Context, &Value<'cx2>) -> ResultExc<Value<'cx2>> + 'static, C: for<'cx2> FnOnce(&'cx2 Context, &Value<'cx2>) -> ResultExc<Value<'cx2>> + 'static,

pub fn then<'cx, F>(&self, cx: &'cx Context, on_resolved: F) -> bool

where F: for<'cx2> FnOnce(&'cx2 Context, &Value<'cx2>) -> ResultExc<Value<'cx2>> + 'static,

pub fn catch<'cx, F>(&self, cx: &'cx Context, on_rejected: F) -> bool

where F: for<'cx2> FnOnce(&'cx2 Context, &Value<'cx2>) -> ResultExc<Value<'cx2>> + 'static,

pub fn add_reactions_native( &self, cx: &Context, on_resolved: Option<Function<'_>>, on_rejected: Option<Function<'_>>, ) -> bool

Adds Reactions to the Promise

on_resolved is similar to calling .then() on a promise.

on_rejected is similar to calling .catch() on a promise.

pub fn resolve(&self, cx: &Context, value: &Value<'_>) -> bool

Resolves the Promise with the given Value.

pub fn reject(&self, cx: &Context, value: &Value<'_>) -> bool

Rejects the Promise with the given Value.

pub fn reject_with_error(&self, cx: &Context, error: &Error) -> bool

Rejects the Promise with the given Error.

pub fn is_promise_raw(cx: &Context, object: *mut JSObject) -> bool

Checks if a *mut JSObject is a promise.

pub fn is_promise(object: &Local<'_, *mut JSObject>) -> bool

Checks if an object is a promise.

Methods from Deref<Target = Local<'p, *mut JSObject>>

pub fn handle(&self) -> Handle<'local, T>

Forms a Handle to the Local which can be passed to SpiderMonkey APIs.

pub fn handle_mut(&mut self) -> MutableHandle<'local, T>

Forms a Handle to the Local which can be passed to SpiderMonkey APIs.

Panics

Panics when a Local::Handle is passed.

pub fn get(&self) -> T

Trait Implementations

impl<'p> Debug for Promise<'p>

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

Formats the value using the given formatter.

impl<'p> Deref for Promise<'p>

type Target = Local<'p, *mut JSObject>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl DerefMut for Promise<'_>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<'cx> FromValue<'cx> for Promise<'cx>

type Config = ()

fn from_value( cx: &'cx Context, value: &Value<'_>, _: bool, _: (), ) -> Result<Promise<'cx>>

Converts value to the desired type. strict and config determine the strictness of the conversion and specify additional conversion constraints respectively. Returns Err with the error if conversion fails.

impl<'cx> ToValue<'cx> for Promise<'cx>

fn to_value(&self, cx: &'cx Context, value: &mut Value<'_>)

Converts self to a Value and stores it in value.

fn as_value(&self, cx: &'cx Context) -> Value<'cx>

Converts self to a new Value.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 16 bytes