✨ signal option for canceling scheduled tasks, resolve #4

src/ScheduledTask.ts

@@ -3,6 +3,7 @@ import type SchedulingTask from './SchedulingTask'
 type ScheduledTask = SchedulingTask & {
     promise: Promise<void>
     resolve: () => void
+    reject: (reason: DOMException) => void
 }
 
 export default ScheduledTask

src/SchedulingTask.ts

@@ -2,4 +2,5 @@ export default interface SchedulingTask {
     type: 'frame-based' | 'idle-based'
     workTime: number
     priority: number
+    signal?: AbortSignal
 }

src/ThreadScheduler.ts

@@ -23,7 +23,17 @@ class ThreadScheduler {
 
     schedule(task: SchedulingTask): ScheduledTask {
         const scheduled = { ...task, ...withResolvers() }
+
         this.#insertTask(scheduled)
+        task.signal?.addEventListener(
+            'abort',
+            () => {
+                this.#removeTask(scheduled)
+                scheduled.reject(new DOMException('The operation was aborted.', 'AbortError'))
+            },
+            { once: true },
+        )
+
         return scheduled
     }
 

src/isTimeToYield.ts

@@ -1,7 +1,7 @@
 import hasValidContext from './utils/hasValidContext'
 import SchedulingStrategy from './SchedulingStrategy'
 import threadScheduler from './ThreadScheduler'
-import strategyToTask from './utils/strategyToTask'
+import toTask from './utils/toTask'
 
 // #performance
 // calling `isTimeToYield()` thousand of times is slow
@@ -34,7 +34,7 @@ export default function isTimeToYield(strategy: SchedulingStrategy = 'smooth'):
     }
 
     cache.lastCallTime = now
-    cache.lastResult = threadScheduler.isTimeToYield(strategyToTask(strategy))
+    cache.lastResult = threadScheduler.isTimeToYield(toTask(strategy))
 
     return cache.lastResult
 }

src/utils/strategyToTask.ts → src/utils/toTask.ts

@@ -1,7 +1,10 @@
 import type SchedulingStrategy from '../SchedulingStrategy'
 import type SchedulingTask from '../SchedulingTask'
 
-export default function strategyToTask(schedulingStrategy: SchedulingStrategy): SchedulingTask {
+export default function toTask(
+    schedulingStrategy: SchedulingStrategy,
+    signal?: AbortSignal,
+): SchedulingTask {
     const options: Record<SchedulingStrategy, SchedulingTask> = {
         interactive: {
             type: 'frame-based',
@@ -19,5 +22,7 @@ export default function strategyToTask(schedulingStrategy: SchedulingStrategy):
             priority: 10,
         },
     }
-    return options[schedulingStrategy]
+    const task = options[schedulingStrategy]
+    task.signal = signal
+    return task
 }

src/yieldControl.ts

@@ -1,7 +1,7 @@
 import hasValidContext from './utils/hasValidContext'
 import SchedulingStrategy from './SchedulingStrategy'
 import threadScheduler from './ThreadScheduler'
-import strategyToTask from './utils/strategyToTask'
+import toTask from './utils/toTask'
 
 /**
  * Waits for the browser to become idle again in order to resume work. Calling `yieldControl()`
@@ -13,10 +13,13 @@ import strategyToTask from './utils/strategyToTask'
  * resolved second.
  * @returns {Promise<void>} A promise that gets resolved when the work can continue.
  */
-export default async function yieldControl(strategy: SchedulingStrategy = 'smooth'): Promise<void> {
+export default async function yieldControl(
+    strategy: SchedulingStrategy = 'smooth',
+    signal?: AbortSignal,
+): Promise<void> {
     if (!hasValidContext()) {
         return
     }
 
-    return threadScheduler.schedule(strategyToTask(strategy)).promise
+    return threadScheduler.schedule(toTask(strategy, signal)).promise
 }

src/yieldOrContinue.ts

@@ -16,9 +16,12 @@ import SchedulingStrategy from './SchedulingStrategy'
  */
 // disabling ESLint otherwise `requestPromiseEscape()` in `yieldControl()` won't work
 // eslint-disable-next-line @typescript-eslint/promise-function-async
-export default function yieldOrContinue(priority: SchedulingStrategy = 'smooth'): Promise<void> {
-    if (isTimeToYield(priority)) {
-        return yieldControl(priority)
+export default function yieldOrContinue(
+    priority: SchedulingStrategy = 'smooth',
+    signal?: AbortSignal,
+): Promise<void> {
+    if (signal?.aborted !== true && isTimeToYield(priority)) {
+        return yieldControl(priority, signal)
     }
 
     return Promise.resolve()