diff --git a/extensions/emmet/src/abbreviationActions.ts b/extensions/emmet/src/abbreviationActions.ts
index 643fea0a2d038..3d91192ae1a77 100644
--- a/extensions/emmet/src/abbreviationActions.ts
+++ b/extensions/emmet/src/abbreviationActions.ts
@@ -289,7 +289,7 @@ export function expandEmmetAbbreviation(args: any): Thenable<boolean | undefined
 		args['language'] = vscode.window.activeTextEditor.document.languageId;
 	} else {
 		const excludedLanguages = vscode.workspace.getConfiguration('emmet')['excludeLanguages'] ? vscode.workspace.getConfiguration('emmet')['excludeLanguages'] : [];
-		if (excludedLanguages.indexOf(vscode.window.activeTextEditor.document.languageId) > -1) {
+		if (excludedLanguages.includes(vscode.window.activeTextEditor.document.languageId)) {
 			return fallbackTab();
 		}
 	}
@@ -527,7 +527,7 @@ export function isValidLocationForEmmetAbbreviation(document: vscode.TextDocumen
 			const typeAttribute = (currentHtmlNode.attributes || []).filter(x => x.name.toString() === 'type')[0];
 			const typeValue = typeAttribute ? typeAttribute.value.toString() : '';
 
-			if (allowedMimeTypesInScriptTag.indexOf(typeValue) > -1) {
+			if (allowedMimeTypesInScriptTag.includes(typeValue)) {
 				return true;
 			}
 
diff --git a/extensions/emmet/src/defaultCompletionProvider.ts b/extensions/emmet/src/defaultCompletionProvider.ts
index c8a6f657d75b6..60cdb2a5cb1e6 100644
--- a/extensions/emmet/src/defaultCompletionProvider.ts
+++ b/extensions/emmet/src/defaultCompletionProvider.ts
@@ -43,7 +43,7 @@ export class DefaultCompletionItemProvider implements vscode.CompletionItemProvi
 	private provideCompletionItemsInternal(document: vscode.TextDocument, position: vscode.Position, context: vscode.CompletionContext): Thenable<vscode.CompletionList | undefined> | undefined {
 		const emmetConfig = vscode.workspace.getConfiguration('emmet');
 		const excludedLanguages = emmetConfig['excludeLanguages'] ? emmetConfig['excludeLanguages'] : [];
-		if (excludedLanguages.indexOf(document.languageId) > -1) {
+		if (excludedLanguages.includes(document.languageId)) {
 			return;
 		}