Add explicit null checks (fixes microsoft/monaco-editor#1376)

alexdima · alexdima · commit 5ba0926f9d35 · 2019-12-12T09:49:17.000+01:00
diff --git a/src/vs/base/common/async.ts b/src/vs/base/common/async.ts
@@ -184,13 +184,14 @@ export class Delayer<T> implements IDisposable {
 	private timeout: any;
 	private completionPromise: Promise<any> | null;
 	private doResolve: ((value?: any | Promise<any>) => void) | null;
-	private doReject?: (err: any) => void;
+	private doReject: ((err: any) => void) | null;
 	private task: ITask<T | Promise<T>> | null;
 
 	constructor(public defaultDelay: number) {
 		this.timeout = null;
 		this.completionPromise = null;
 		this.doResolve = null;
+		this.doReject = null;
 		this.task = null;
 	}
 
@@ -205,16 +206,20 @@ export class Delayer<T> implements IDisposable {
 			}).then(() => {
 				this.completionPromise = null;
 				this.doResolve = null;
-				const task = this.task!;
-				this.task = null;
-
-				return task();
+				if (this.task) {
+					const task = this.task;
+					this.task = null;
+					return task();
+				}
+				return undefined;
 			});
 		}
 
 		this.timeout = setTimeout(() => {
 			this.timeout = null;
-			this.doResolve!(null);
+			if (this.doResolve) {
+				this.doResolve(null);
+			}
 		}, delay);
 
 		return this.completionPromise;
@@ -228,7 +233,9 @@ export class Delayer<T> implements IDisposable {
 		this.cancelTimeout();
 
 		if (this.completionPromise) {
-			this.doReject!(errors.canceled());
+			if (this.doReject) {
+				this.doReject(errors.canceled());
+			}
 			this.completionPromise = null;
 		}
 	}
