Start moving html ext to strict mode compile

Moves the html extension's client code to strict mode and also updates some of the server code. The rest of this migration will requires changes to the *.d.ts files that the server consumes

extensions/html/server/src/modes/embeddedSupport.ts

@@ -29,9 +29,9 @@ export function getDocumentRegions(languageService: LanguageService, document: T
 	let regions: EmbeddedRegion[] = [];
 	let scanner = languageService.createScanner(document.getText());
 	let lastTagName: string;
-	let lastAttributeName: string;
-	let languageIdFromType: string;
-	let importedScripts = [];
+	let lastAttributeName: string | null;
+	let languageIdFromType: string | undefined = undefined;
+	let importedScripts: string[] = [];
 
 	let token = scanner.scan();
 	while (token !== TokenType.EOS) {
@@ -224,7 +224,7 @@ function append(result: string, str: string, n: number): string {
 	return result;
 }
 
-function getAttributeLanguage(attributeName: string): string {
+function getAttributeLanguage(attributeName: string): string | null {
 	let match = attributeName.match(/^(style)$|^(on\w+)$/i);
 	if (!match) {
 		return null;

extensions/html/server/src/modes/htmlMode.ts

@@ -60,7 +60,6 @@ export function getHTMLMode(htmlLanguageService: HTMLLanguageService): LanguageM
 			if (offset > 0 && text.charAt(offset - 1).match(/[>\/]/g)) {
 				return htmlLanguageService.doTagComplete(document, position, htmlDocuments.get(document));
 			}
-			return null;
 		},
 		onDocumentRemoved(document: TextDocument) {
 			htmlDocuments.onDocumentRemoved(document);

extensions/html/server/src/modes/javascriptMode.ts

@@ -73,7 +73,7 @@ export function getJavascriptMode(documentRegions: LanguageModelCache<HTMLDocume
 			updateCurrentTextDocument(document);
 			const syntaxDiagnostics = jsLanguageService.getSyntacticDiagnostics(FILE_NAME);
 			const semanticDiagnostics = jsLanguageService.getSemanticDiagnostics(FILE_NAME);
-			return syntaxDiagnostics.concat(semanticDiagnostics).map((diag): Diagnostic => {
+			return syntaxDiagnostics.concat(semanticDiagnostics).map((diag: ts.Diagnostic): Diagnostic => {
 				return {
 					range: convertRange(currentTextDocument, diag),
 					severity: DiagnosticSeverity.Error,
@@ -143,7 +143,7 @@ export function getJavascriptMode(documentRegions: LanguageModelCache<HTMLDocume
 
 					let signature: SignatureInformation = {
 						label: '',
-						documentation: null,
+						documentation: undefined,
 						parameters: []
 					};
 
@@ -185,7 +185,7 @@ export function getJavascriptMode(documentRegions: LanguageModelCache<HTMLDocume
 			let items = jsLanguageService.getNavigationBarItems(FILE_NAME);
 			if (items) {
 				let result: SymbolInformation[] = [];
-				let existing = {};
+				let existing = Object.create(null);
 				let collectSymbols = (item: ts.NavigationBarItem, containerLabel?: string) => {
 					let sig = item.text + item.kind + item.spans[0].start;
 					if (item.kind !== 'script' && !existing[sig]) {
@@ -288,9 +288,13 @@ export function getJavascriptMode(documentRegions: LanguageModelCache<HTMLDocume
 	};
 };
 
-function convertRange(document: TextDocument, span: { start: number, length: number }): Range {
-	let startPosition = document.positionAt(span.start);
-	let endPosition = document.positionAt(span.start + span.length);
+function convertRange(document: TextDocument, span: { start: number | undefined, length: number | undefined }): Range {
+	if (typeof span.start === 'undefined') {
+		const pos = document.positionAt(0);
+		return Range.create(pos, pos);
+	}
+	const startPosition = document.positionAt(span.start);
+	const endPosition = document.positionAt(span.start + (span.length || 0));
 	return Range.create(startPosition, endPosition);
 }
 

extensions/html/server/src/modes/languageModes.ts

@@ -31,7 +31,7 @@ export interface SettingProvider {
 }
 
 export interface LanguageMode {
-	getId();
+	getId(): string;
 	configure?: (options: Settings) => void;
 	doValidation?: (document: TextDocument, settings?: Settings) => Diagnostic[];
 	doComplete?: (document: TextDocument, position: Position, settings?: Settings) => CompletionList;
@@ -74,7 +74,7 @@ export function getLanguageModes(supportedLanguages: { [languageId: string]: boo
 	let modelCaches: LanguageModelCache<any>[] = [];
 	modelCaches.push(documentRegions);
 
-	let modes = {};
+	let modes = Object.create(null);
 	modes['html'] = getHTMLMode(htmlLanguageService);
 	if (supportedLanguages['css']) {
 		modes['css'] = getCSSMode(documentRegions);

extensions/html/server/src/test/javascriptMode.test.ts

@@ -27,7 +27,7 @@ suite('HTML Javascript Support', () => {
 		var mode = getJavascriptMode(documentRegions);
 
 		let position = document.positionAt(offset);
-		let list = mode.doComplete(document, position);
+		let list = mode.doComplete!(document, position);
 		assert.ok(list);
 
 		let actualLabels = list.items.map(c => c.label).sort();