quickjs-emscripten

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quickjs-emscripten / quickjs-emscripten-core / QuickJSDeferredPromise

Class: QuickJSDeferredPromise

Defined in: packages/quickjs-emscripten-core/src/deferred-promise.ts:71

QuickJSDeferredPromise wraps a QuickJS promise handle and allows resolveing or rejecting that promise. Use it to bridge asynchronous code on the host to APIs inside a QuickJSContext.

Managing the lifetime of promises is tricky. There are three QuickJSHandles inside of each deferred promise object: (1) the promise itself, (2) the resolve callback, and (3) the reject callback.

• If the promise will be fulfilled before the end of it's owner's lifetime, the only cleanup necessary is deferred.handle.dispose(), because calling resolve or reject will dispose of both callbacks automatically.

• As the return value of a VmFunctionImplementation, return handle, and ensure that either resolve or reject will be called. No other clean-up is necessary.

• In other cases, call dispose, which will dispose handle as well as the QuickJS handles that back resolve and reject. For this object, dispose is idempotent.

Contents

• Extends
• Implements
• Constructors
  • Constructor
• Properties
  • context
  • handle
  • owner
  • settled
• Accessors
  • alive
• Methods
  • [dispose]()
  • dispose()
  • reject()
  • resolve()

Extends

• UsingDisposable

Implements

• Disposable

Constructors

Constructor

new QuickJSDeferredPromise(args): QuickJSDeferredPromise

Defined in: packages/quickjs-emscripten-core/src/deferred-promise.ts:95

Use QuickJSContext#newPromise to create a new promise instead of calling this constructor directly.

Parameters

args

context

QuickJSContext

promiseHandle

QuickJSHandle

rejectHandle

QuickJSHandle

resolveHandle

QuickJSHandle

Returns

QuickJSDeferredPromise

Overrides

UsingDisposable.constructor

Properties

context

context: QuickJSContext

Defined in: packages/quickjs-emscripten-core/src/deferred-promise.ts:73

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handle

handle: QuickJSHandle

Defined in: packages/quickjs-emscripten-core/src/deferred-promise.ts:80

A handle of the Promise instance inside the QuickJSContext. You must dispose handle or the entire QuickJSDeferredPromise once you are finished with it.

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owner

owner: QuickJSRuntime

Defined in: packages/quickjs-emscripten-core/src/deferred-promise.ts:72

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settled

settled: Promise<void>

Defined in: packages/quickjs-emscripten-core/src/deferred-promise.ts:85

A native promise that will resolve once this deferred is settled.

Accessors

alive

Get Signature

get alive(): boolean

Defined in: packages/quickjs-emscripten-core/src/deferred-promise.ts:166

Returns

boolean

true if the object is alive

Implementation of

Disposable.alive

Overrides

UsingDisposable.alive

Methods

[dispose]()

[dispose](): void

Defined in: packages/quickjs-emscripten-core/src/lifetime.ts:47

Just calls the standard .dispose() method of this class.

Returns

void

Implementation of

Disposable.[dispose]

Inherited from

UsingDisposable.[dispose]

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dispose()

dispose(): void

Defined in: packages/quickjs-emscripten-core/src/deferred-promise.ts:170

Dispose of the underlying resources used by this object.

Returns

void

Implementation of

Disposable.dispose

Overrides

UsingDisposable.dispose

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reject()

reject(value?): void

Defined in: packages/quickjs-emscripten-core/src/deferred-promise.ts:147

Reject handle with the given value, if any. Calling this method after calling dispose is a no-op.

Note that after rejecting a promise, you may need to call QuickJSRuntime#executePendingJobs to propagate the result to the promise's callbacks.

Parameters

value?

QuickJSHandle

Returns

void

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resolve()

resolve(value?): void

Defined in: packages/quickjs-emscripten-core/src/deferred-promise.ts:120

Resolve handle with the given value, if any. Calling this method after calling dispose is a no-op.

Note that after resolving a promise, you may need to call QuickJSRuntime#executePendingJobs to propagate the result to the promise's callbacks.

Parameters

value?

QuickJSHandle

Returns

void