Class CancellablePromise<T>

A promise that can be cancelled before completion.

Extends the native Promise class to add cancellation support. When cancelled, the promise resolves (not rejects) and calls an optional cleanup callback.

This is useful for animations and effects that need to be interruptible, allowing the final state to be shown immediately instead of waiting.

CancellablePromise

Example

const promise = new CancellablePromise(
  (resolve) => {
    setTimeout(resolve, 5000); // Would take 5 seconds
  },
  () => {
    console.log("Cancelled! Cleaning up...");
  }
);

// Cancel after 1 second
setTimeout(() => promise.cancel(), 1000);

Type Parameters

T = void
The type of value the promise resolves to (default: void)

Hierarchy

Promise<T>
- CancellablePromise

Index

Constructors

constructor

new CancellablePromise<T = void>(
    executor: (
        resolve: (value: T | PromiseLike<T>) => void,
        reject: (reason?: any) => void,
    ) => void,
    onCancel?: () => void,
): CancellablePromise<T>
Creates a new CancellablePromise.
Type Parameters
- T = void
  The type of value the promise resolves to (default: void)
Parameters
- executor: (
  resolve: (value: T | PromiseLike<T>) => void,
  reject: (reason?: any) => void,
  ) => void
  The executor function, same as native Promise. Receives resolve and reject callbacks.
- OptionalonCancel: () => void
  Optional cleanup callback invoked when cancel() is called. This runs before the promise resolves, allowing cleanup of timers, intervals, etc.
Returns CancellablePromise<T>
Overrides Promise<T>.constructor
- Defined in src/util/promise.ts:47

Properties

`Readonly`[toStringTag]

"[toStringTag]": string

`Static` `Readonly`[species]

"[species]": PromiseConstructor

Accessors

cancelled

get cancelled(): boolean
Gets whether the promise has been cancelled.

Returns boolean
True if cancelled, false otherwise
- Defined in src/util/promise.ts:73
set cancelled(value: boolean): void
Sets whether the promise has been cancelled.
Parameters
- value: boolean
  The cancelled state
Returns void
- Defined in src/util/promise.ts:81

Methods

cancel

cancel(value?: T): void
Cancels the promise, invoking the cleanup callback and resolving immediately.

This method:
1. Marks the promise as cancelled
2. Calls the onCancel callback (if provided) for cleanup
3. Resolves the promise with the provided value (or undefined for void promises)
Calling cancel() multiple times has no effect after the first call.
Parameters
- Optionalvalue: T
  Optional value to resolve the promise with. For void promises (default), this can be omitted.
Returns void
- Defined in src/util/promise.ts:98

catch

catch<TResult = never>(
onrejected?: ((reason: any) => TResult | PromiseLike<TResult>) | null,
): Promise<T | TResult>
Attaches a callback for only the rejection of the Promise.
Type Parameters
- TResult = never
Parameters
- Optionalonrejected: ((reason: any) => TResult | PromiseLike<TResult>) | null
  The callback to execute when the Promise is rejected.
Returns Promise<T | TResult>
A Promise for the completion of the callback.
Inherited from Promise.catch
- Defined in node_modules/typescript/lib/lib.es5.d.ts:1564

finally

finally(onfinally?: (() => void) | null): Promise<T>
Attaches a callback that is invoked when the Promise is settled (fulfilled or rejected). The resolved value cannot be modified from the callback.
Parameters
- Optionalonfinally: (() => void) | null
  The callback to execute when the Promise is settled (fulfilled or rejected).
Returns Promise<T>
A Promise for the completion of the callback.
Inherited from Promise.finally
- Defined in node_modules/typescript/lib/lib.es2018.promise.d.ts:29

then

then<TResult1 = T, TResult2 = never>(
onfulfilled?: ((value: T) => TResult1 | PromiseLike<TResult1>) | null,
onrejected?: ((reason: any) => TResult2 | PromiseLike<TResult2>) | null,
): Promise<TResult1 | TResult2>
Attaches callbacks for the resolution and/or rejection of the Promise.
Type Parameters
- TResult1 = T
- TResult2 = never
Parameters
- Optionalonfulfilled: ((value: T) => TResult1 | PromiseLike<TResult1>) | null
  The callback to execute when the Promise is resolved.
- Optionalonrejected: ((reason: any) => TResult2 | PromiseLike<TResult2>) | null
  The callback to execute when the Promise is rejected.
Returns Promise<TResult1 | TResult2>
A Promise for the completion of which ever callback is executed.
Inherited from Promise.then
- Defined in node_modules/typescript/lib/lib.es5.d.ts:1557

`Static`all

all<T>(values: Iterable<T | PromiseLike<T>>): Promise<Awaited<T>[]>
Creates a Promise that is resolved with an array of results when all of the provided Promises resolve, or rejected when any Promise is rejected.
Type Parameters
- T
Parameters
- values: Iterable<T | PromiseLike<T>>
  An iterable of Promises.
Returns Promise<Awaited<T>[]>
A new Promise.
Inherited from Promise.all
- Defined in node_modules/typescript/lib/lib.es2015.iterable.d.ts:255
all<T extends [] | readonly unknown[]>(
values: T,
): Promise<{ -readonly [P in string | number | symbol]: Awaited<T[P<P>]> }>
Creates a Promise that is resolved with an array of results when all of the provided Promises resolve, or rejected when any Promise is rejected.
Type Parameters
- T extends [] | readonly unknown[]
Parameters
- values: T
  An array of Promises.
Returns Promise<{ -readonly [P in string | number | symbol]: Awaited<T[P<P>]> }>
A new Promise.
Inherited from Promise.all
- Defined in node_modules/typescript/lib/lib.es2015.promise.d.ts:39

`Static`allSettled

allSettled<T extends [] | readonly unknown[]>(
    values: T,
): Promise<
    {
        -readonly [P in string
        | number
        | symbol]: PromiseSettledResult<Awaited<T[P<P>]>>
    },
>
Creates a Promise that is resolved with an array of results when all of the provided Promises resolve or reject.
Type Parameters
- T extends [] | readonly unknown[]
Parameters
- values: T
  An array of Promises.
Returns Promise<
    {
        -readonly [P in string
        | number
        | symbol]: PromiseSettledResult<Awaited<T[P<P>]>>
    },
>
A new Promise.
Inherited from Promise.allSettled
- Defined in node_modules/typescript/lib/lib.es2020.promise.d.ts:38
allSettled<T>(
values: Iterable<T | PromiseLike<T>>,
): Promise<PromiseSettledResult<Awaited<T>>[]>
Creates a Promise that is resolved with an array of results when all of the provided Promises resolve or reject.
Type Parameters
- T
Parameters
- values: Iterable<T | PromiseLike<T>>
  An array of Promises.
Returns Promise<PromiseSettledResult<Awaited<T>>[]>
A new Promise.
Inherited from Promise.allSettled
- Defined in node_modules/typescript/lib/lib.es2020.promise.d.ts:46

`Static`any

any<T extends [] | readonly unknown[]>(values: T): Promise<Awaited<T[number]>>
The any function returns a promise that is fulfilled by the first given promise to be fulfilled, or rejected with an AggregateError containing an array of rejection reasons if all of the given promises are rejected. It resolves all elements of the passed iterable to promises as it runs this algorithm.
Type Parameters
- T extends [] | readonly unknown[]
Parameters
- values: T
  An array or iterable of Promises.
Returns Promise<Awaited<T[number]>>
A new Promise.
Inherited from Promise.any
- Defined in node_modules/typescript/lib/lib.es2021.promise.d.ts:40
any<T>(values: Iterable<T | PromiseLike<T>>): Promise<Awaited<T>>
The any function returns a promise that is fulfilled by the first given promise to be fulfilled, or rejected with an AggregateError containing an array of rejection reasons if all of the given promises are rejected. It resolves all elements of the passed iterable to promises as it runs this algorithm.
Type Parameters
- T
Parameters
- values: Iterable<T | PromiseLike<T>>
  An array or iterable of Promises.
Returns Promise<Awaited<T>>
A new Promise.
Inherited from Promise.any
- Defined in node_modules/typescript/lib/lib.es2021.promise.d.ts:47

`Static`race

race<T>(values: Iterable<T | PromiseLike<T>>): Promise<Awaited<T>>
Creates a Promise that is resolved or rejected when any of the provided Promises are resolved or rejected.
Type Parameters
- T
Parameters
- values: Iterable<T | PromiseLike<T>>
  An iterable of Promises.
Returns Promise<Awaited<T>>
A new Promise.
Inherited from Promise.race
- Defined in node_modules/typescript/lib/lib.es2015.iterable.d.ts:263
race<T extends [] | readonly unknown[]>(values: T): Promise<Awaited<T[number]>>
Creates a Promise that is resolved or rejected when any of the provided Promises are resolved or rejected.
Type Parameters
- T extends [] | readonly unknown[]
Parameters
- values: T
  An array of Promises.
Returns Promise<Awaited<T[number]>>
A new Promise.
Inherited from Promise.race
- Defined in node_modules/typescript/lib/lib.es2015.promise.d.ts:50

`Static`reject

reject<T = never>(reason?: any): Promise<T>
Creates a new rejected promise for the provided reason.
Type Parameters
- T = never
Parameters
- Optionalreason: any
  The reason the promise was rejected.
Returns Promise<T>
A new rejected Promise.
Inherited from Promise.reject
- Defined in node_modules/typescript/lib/lib.es2015.promise.d.ts:60

`Static`resolve

resolve(): Promise<void>
Creates a new resolved promise.

Returns Promise<void>
A resolved promise.
Inherited from Promise.resolve
- Defined in node_modules/typescript/lib/lib.es2015.promise.d.ts:66
resolve<T>(value: T): Promise<Awaited<T>>
Creates a new resolved promise for the provided value.
Type Parameters
- T
Parameters
- value: T
  A promise.
Returns Promise<Awaited<T>>
A promise whose internal state matches the provided promise.
Inherited from Promise.resolve
- Defined in node_modules/typescript/lib/lib.es2015.promise.d.ts:72
resolve<T>(value: T | PromiseLike<T>): Promise<Awaited<T>>
Creates a new resolved promise for the provided value.
Type Parameters
- T
Parameters
- value: T | PromiseLike<T>
  A promise.
Returns Promise<Awaited<T>>
A promise whose internal state matches the provided promise.
Inherited from Promise.resolve
- Defined in node_modules/typescript/lib/lib.es2015.promise.d.ts:78

`Static`try

try<T, U extends unknown[]>(
callbackFn: (...args: U) => T | PromiseLike<T>,
...args: U,
): Promise<Awaited<T>>
Takes a callback of any kind (returns or throws, synchronously or asynchronously) and wraps its result in a Promise.
Type Parameters
- T
- U extends unknown[]
Parameters
- callbackFn: (...args: U) => T | PromiseLike<T>
  A function that is called synchronously. It can do anything: either return a value, throw an error, or return a promise.
- ...args: U
  Additional arguments, that will be passed to the callback.
Returns Promise<Awaited<T>>
A Promise that is:
- Already fulfilled, if the callback synchronously returns a value.
- Already rejected, if the callback synchronously throws an error.
- Asynchronously fulfilled or rejected, if the callback returns a promise.
Inherited from Promise.try
- Defined in node_modules/typescript/lib/lib.esnext.promise.d.ts:33

`Static`withResolvers

withResolvers<T>(): PromiseWithResolvers<T>
Creates a new Promise and returns it in an object, along with its resolve and reject functions.
Type Parameters
- T
Returns PromiseWithResolvers<T>
An object with the properties promise, resolve, and reject.
```
const { promise, resolve, reject } = Promise.withResolvers<T>();
```
Inherited from Promise.withResolvers
- Defined in node_modules/typescript/lib/lib.es2024.promise.d.ts:34

Class CancellablePromise<T>

Example

Type Parameters

Hierarchy

Index

Constructors

Properties

Accessors

Methods

Constructors

constructor

Type Parameters

Parameters

Returns CancellablePromise<T>

Properties

Readonly[toStringTag]

Static Readonly[species]

Accessors

cancelled

Returns boolean

Parameters

Returns void

Methods

cancel

Parameters

Returns void

catch

Type Parameters

Parameters

Returns Promise<T | TResult>

finally

Parameters

Returns Promise<T>

then

Type Parameters

Parameters

Returns Promise<TResult1 | TResult2>

Staticall

Type Parameters

Parameters

Returns Promise<Awaited<T>[]>

Type Parameters

Parameters

Returns Promise<{ -readonly [P in string | number | symbol]: Awaited<T[P<P>]> }>

StaticallSettled

Type Parameters

Parameters

Returns Promise< { -readonly [P in string | number | symbol]: PromiseSettledResult<Awaited<T[P<P>]>> },>

Type Parameters

Parameters

Returns Promise<PromiseSettledResult<Awaited<T>>[]>

Staticany

Type Parameters

Parameters

Returns Promise<Awaited<T[number]>>

Type Parameters

Parameters

Returns Promise<Awaited<T>>

Staticrace

Type Parameters

Parameters

Returns Promise<Awaited<T>>

Type Parameters

Parameters

Returns Promise<Awaited<T[number]>>

Staticreject

Type Parameters

Parameters

Returns Promise<T>

Staticresolve

Returns Promise<void>

Type Parameters

Parameters

Returns Promise<Awaited<T>>

Type Parameters

Parameters

Returns Promise<Awaited<T>>

Statictry

Type Parameters

Parameters

`Readonly`[toStringTag]

`Static` `Readonly`[species]

`Static`all

`Static`allSettled

Returns Promise<
{
-readonly [P in string
| number
| symbol]: PromiseSettledResult<Awaited<T[P<P>]>>
},
>

`Static`any

`Static`race

`Static`reject

`Static`resolve

`Static`try

`Static`withResolvers