Update to TypeScript 3.9

bench.ts

@@ -5,7 +5,7 @@ import PQueue from './source';
 const suite = new Benchmark.Suite();
 
 // Benchmark typings aren't up to date, let's help out manually
-type Resolvable = Deferred & {resolve(): void};
+type Resolvable = Deferred & {resolve: () => void};
 
 suite
 	.add('baseline', {
@@ -54,15 +54,15 @@ suite
 			}
 
 			await queue.onEmpty();
-			// @ts-ignore benchmark typings incorrect
+			// @ts-expect-error benchmark typings incorrect
 			deferred.resolve();
 		}
 	})
 	.on('cycle', (event: Event) => {
 		console.log(String(event.target));
 	})
 	.on('complete', function () {
-		// @ts-ignore benchmark typings incorrect
+		// @ts-expect-error benchmark typings incorrect
 		console.log(`Fastest is ${(this as Benchmark.Suite).filter('fastest').map('name') as string}`);
 	})
 	.run({

package.json

@@ -46,9 +46,9 @@
 		"p-timeout": "^3.1.0"
 	},
 	"devDependencies": {
-		"@sindresorhus/tsconfig": "^0.6.0",
+		"@sindresorhus/tsconfig": "^0.7.0",
 		"@types/benchmark": "^1.0.31",
-		"@types/node": "^12.12.7",
+		"@types/node": "^14.0.14",
 		"ava": "^2.0.0",
 		"benchmark": "^2.1.4",
 		"codecov": "^3.3.0",
@@ -59,8 +59,8 @@
 		"random-int": "^2.0.0",
 		"time-span": "^4.0.0",
 		"ts-node": "^8.3.0",
-		"typescript": "3.8.3",
-		"xo": "^0.28.1"
+		"typescript": "^3.9.5",
+		"xo": "^0.32.0"
 	},
 	"ava": {
 		"babel": false,
@@ -79,7 +79,10 @@
 		"rules": {
 			"@typescript-eslint/member-ordering": "off",
 			"@typescript-eslint/prefer-readonly-parameter-types": "off",
-			"node/no-unsupported-features/es-syntax": "off"
+			"node/no-unsupported-features/es-syntax": "off",
+			"@typescript-eslint/no-floating-promises": "off",
+			"import/no-named-default": "off",
+			"@typescript-eslint/no-invalid-void-type": "off"
 		}
 	},
 	"nyc": {

source/index.ts

@@ -351,6 +351,7 @@ export default class PQueue<QueueType extends Queue<RunFunction, EnqueueOptionsT
 	For example, this can be used to find the number of items remaining in the queue with a specific priority level.
 	*/
 	sizeBy(options: Readonly<Partial<EnqueueOptionsType>>): number {
+		// eslint-disable-next-line unicorn/no-fn-reference-in-iterator
 		return this._queue.filter(options).length;
 	}
 

source/queue.ts

@@ -2,7 +2,7 @@ export type RunFunction = () => Promise<unknown>;
 
 export interface Queue<Element, Options> {
 	size: number;
-	filter(options: Partial<Options>): Element[];
-	dequeue(): Element | undefined;
-	enqueue(run: Element, options?: Partial<Options>): void;
+	filter: (options: Partial<Options>) => Element[];
+	dequeue: () => Element | undefined;
+	enqueue: (run: Element, options?: Partial<Options>) => void;
 }

test/test.ts

@@ -47,6 +47,7 @@ test('.add() - concurrency: 1', async t => {
 		return value;
 	});
 
+	// eslint-disable-next-line unicorn/no-fn-reference-in-iterator
 	t.deepEqual(await Promise.all(input.map(mapper)), [10, 20, 30]);
 	t.true(inRange(end(), {start: 590, end: 650}));
 });
@@ -296,7 +297,7 @@ test('enforce number in queue.concurrency', t => {
 
 	t.throws(
 		() => {
-			// @ts-ignore
+			// @ts-expect-error
 			(new PQueue()).concurrency = undefined;
 		},
 		TypeError