Fix some strict null errors revealed by change to emitter

extensions/npm/src/npmView.ts

@@ -225,7 +225,7 @@ export class NpmScriptsTreeDataProvider implements TreeDataProvider<TreeItem> {
 
 	public refresh() {
 		this.taskTree = null;
-		this._onDidChangeTreeData.fire();
+		this._onDidChangeTreeData.fire(null);
 	}
 
 	getTreeItem(element: TreeItem): TreeItem {

extensions/typescript-language-features/src/typescriptServiceClient.ts

@@ -405,7 +405,7 @@ export default class TypeScriptServiceClient extends Disposable implements IType
 		handle.onEvent(event => this.dispatchEvent(event));
 
 		this._onReady!.resolve();
-		this._onTsServerStarted.fire(version.apiVersion);
+		this._onTsServerStarted.fire(apiVersion);
 
 		if (apiVersion.gte(API.v300)) {
 			this.loadingIndicator.startedLoadingProject(undefined /* projectName */);

extensions/vscode-api-tests/src/singlefolder-tests/terminal.test.ts

@@ -440,7 +440,7 @@ import { doesNotThrow, equal, ok, deepEqual, throws } from 'assert';
 				const pty: Pseudoterminal = {
 					onDidWrite: writeEmitter.event,
 					onDidClose: closeEmitter.event,
-					open: () => closeEmitter.fire(),
+					open: () => closeEmitter.fire(undefined),
 					close: () => { }
 				};
 				const terminal = window.createTerminal({ name: 'foo', pty });