diff --git a/extensions/emmet/src/test/completion.test.ts b/extensions/emmet/src/test/completion.test.ts
index 728dc26a3b3..91844f69f24 100644
--- a/extensions/emmet/src/test/completion.test.ts
+++ b/extensions/emmet/src/test/completion.test.ts
@@ -37,6 +37,13 @@ suite('Tests for completion in CSS embedded in HTML', () => {
 			{ label: 'widows: ;', documentation: `widows: ;` }
 		]);
 	});
+
+	// https://github.com/microsoft/vscode/issues/117020
+	test('#117020, ! at end of abbreviation should have completion', async () => {
+		await testCssCompletionProvider(`.foo { bdbn!| }`, [
+			{ label: 'border-bottom: none !important;', documentation: `border-bottom: none !important;` }
+		]);
+	});
 });
 
 interface TestCompletionItem {
diff --git a/extensions/emmet/src/util.ts b/extensions/emmet/src/util.ts
index 17ad4fbefec..664c0eb6a30 100644
--- a/extensions/emmet/src/util.ts
+++ b/extensions/emmet/src/util.ts
@@ -62,18 +62,18 @@ export const LANGUAGE_MODES: { [id: string]: string[] } = {
 	'haml': ['!', '.', '}', ':', '*', '$', ']', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
 	'xml': ['.', '}', '*', '$', ']', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
 	'xsl': ['!', '.', '}', '*', '$', ']', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
-	'css': [':', '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
-	'scss': [':', '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
-	'sass': [':', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
-	'less': [':', '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
-	'stylus': [':', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
+	'css': [':', '!', '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
+	'scss': [':', '!', '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
+	'sass': [':', '!', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
+	'less': [':', '!', '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
+	'stylus': [':', '!', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
 	'javascriptreact': ['!', '.', '}', '*', '$', ']', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'],
 	'typescriptreact': ['!', '.', '}', '*', '$', ']', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
 };
 
 export function isStyleSheet(syntax: string): boolean {
 	let stylesheetSyntaxes = ['css', 'scss', 'sass', 'less', 'stylus'];
-	return (stylesheetSyntaxes.indexOf(syntax) > -1);
+	return stylesheetSyntaxes.includes(syntax);
 }
 
 export function validate(allowStylesheet: boolean = true): boolean {