Avoid direct compare with null if we only care that some obj is returned

src/vs/workbench/browser/composite.ts

@@ -257,7 +257,7 @@ export abstract class CompositeRegistry<T extends Composite> extends Disposable
 
 	protected deregisterComposite(id: string): void {
 		const descriptor = this.compositeById(id);
-		if (descriptor === null) {
+		if (!descriptor) {
 			return;
 		}
 

src/vs/workbench/contrib/markers/browser/markersTreeViewer.ts

@@ -601,7 +601,7 @@ export class MarkerViewModel extends Disposable {
 			return Promise.resolve(model);
 		}
 		if (waitForModel) {
-			if (this.modelPromise === null) {
+			if (!this.modelPromise) {
 				this.modelPromise = createCancelablePromise(cancellationToken => {
 					return new Promise((c) => {
 						this._register(this.modelService.onModelAdded(model => {