Support AbortController (#161)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

.github/workflows/main.yml

@@ -10,11 +10,10 @@ jobs:
       fail-fast: false
       matrix:
         node-version:
-          - 14
-          - 12
+          - 16
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/setup-node@v1
+      - uses: actions/setup-node@v2
         with:
           node-version: ${{ matrix.node-version }}
       - run: npm install

readme.md

@@ -118,7 +118,7 @@ Note: If your items can potentially throw an exception, you must handle those er
 
 Type: `Function`
 
-Promise-returning/async function.
+Promise-returning/async function. When executed, it will receive `{signal}` as the first argument.
 
 #### options
 
@@ -131,6 +131,41 @@ Default: `0`
 
 Priority of operation. Operations with greater priority will be scheduled first.
 
+##### signal
+
+[`AbortSignal`](https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal) for cancellation of the operation. When aborted, it will be removed from the queue and the `queue.add()` call will reject with an `AbortError`. If the operation is already running, the signal will need to be handled by the operation itself.
+
+```js
+import PQueue, {AbortError} from 'p-queue';
+import got, {CancelError} from 'got';
+
+const queue = new PQueue();
+
+const controller = new AbortController();
+
+try {
+	await queue.add(({signal}) => {
+		const request = got('https://sindresorhus.com');
+
+		signal.addEventListener('abort', () => {
+			request.cancel();
+		});
+
+		try {
+			return await request;
+		} catch (error) {
+			if (!(error instanceof CancelError)) {
+				throw error;
+			}
+		}
+	}, {signal: controller.signal});
+} catch (error) {
+	if (!(error instanceof AbortError)) {
+		throw error;
+	}
+}
+```
+
 #### .addAll(fns, options?)
 
 Same as `.add()`, but accepts an array of sync or async functions and returns a promise that resolves when all functions are resolved.
@@ -327,6 +362,10 @@ await queue.add(() => delay(600));
 //=> 'Task is completed.  Size: 0  Pending: 0'
 ```
 
+### AbortError
+
+The error thrown by `queue.add()` when a job is aborted before it is run. See [`signal`](#signal).
+
 ## Advanced example
 
 A more advanced example to help you understand the flow.