AsyncDisposable Namespace

Package: @esfx/disposable

Functions

create(disposeAsync)

Creates an AsyncDisposable wrapper around a callback used to dispose resources.

NOTE: This is not spec-compliant and will not be standardized. It is preferred to use an AsyncDisposableStack or to implement AsyncDisposable.asyncDispose yourself instead.

Declaration

function create(disposeAsync: () => void | PromiseLike<void>): AsyncDisposable;

Parameters

disposeAsync

() => void | PromiseLike<void>

Returns

AsyncDisposable

hasInstance(value)

Determines whether a value is AsyncDisposable.

NOTE: This is not spec-compliant and will not be standardized.

Declaration

function hasInstance(value: unknown): value is AsyncDisposable;

Parameters

value

unknown

Returns

value is AsyncDisposable

scope()

Emulate using await using for..await..of.

NOTE: This is not spec-compliant and will not be standardized.

Declaration

function scope(): AsyncGenerator<AsyncDisposableScope, void, undefined>;

Returns

AsyncGenerator<AsyncDisposableScope, void, undefined>

Examples

// with `using await` (proposed)
{
  ...
  using await x = expr, y = expr;
  ...
}

// with `AsyncDisposable.scope()`:
for await (const { using, fail } of AsyncDisposable.scope()) {
  try {
    ...
    const x = using(expr), y = using(expr);
    ...
  }
  catch (e) {
    fail(e);
  }
}

usingEach(iterable)

Yields each disposable in the iterable, disposing it when the generator resumes.

This emulates for (using await x of expr).

NOTE: This is not spec-compliant and will not be standardized.

Declaration

function usingEach(iterable: AsyncIterable<AsyncDisposable | Disposable | null | undefined> | Iterable<AsyncDisposable | Disposable | null | undefined | PromiseLike<AsyncDisposable | Disposable | null | undefined>>): AsyncGenerator<AsyncDisposable | Disposable | null | undefined, void, unknown>;

Parameters

iterable

AsyncIterable<AsyncDisposable | Disposable | null | undefined> | Iterable<AsyncDisposable | Disposable | null | undefined | PromiseLike<AsyncDisposable | Disposable | null | undefined>>

Returns

AsyncGenerator<AsyncDisposable | Disposable | null | undefined, void, unknown>

Examples

// with `using await` (proposed)
for (using await x of expr) {
  ...
}
for await (using await x of expr) {
  ...
}

// with `Disposable.usingEach()`:
for await (const x of Disposable.usingEach(expr)) {
  ...
}

Variables

asyncDispose

A well-known symbol used to define an async explicit resource disposal method on an object.

NOTE: Uses Symbol.asyncDispose if present.

Declaration

asyncDispose: AsyncDisposeSymbol