Option to trigger emmet expansion on tab (#32334)

extensions/emmet/package.json

@@ -74,6 +74,11 @@
                     "type": "string",
                     "default": null,
                     "description": "%emmetExtensionsPath%"
+                },
+                "emmet.triggerExpansionOnTab": {
+                    "type": "boolean",
+                    "default": false,
+                    "description": "%emmetTriggerExpansionOnTab%"
                 }
             }
         },

extensions/emmet/package.nls.json

@@ -28,5 +28,6 @@
 	"emmetShowExpandedAbbreviation": "Shows expanded emmet abbreviations as suggestions.\nThe option \"inMarkupAndStylesheetFilesOnly\" applies to html, haml, jade, slim, xml, xsl, css, scss, sass, less and stylus.\nThe option \"always\" applies to all parts of the file regardless of markup/css.",
 	"emmetShowAbbreviationSuggestions": "Shows possible emmet abbreviations as suggestions. Not applicable in stylesheets or when emmet.showExpandedAbbreviation is set to \"never\".",
 	"emmetIncludeLanguages": "Enable emmet abbreviations in languages that are not supported by default. Add a mapping here between the language and emmet supported language.\n Eg: {\"vue-html\": \"html\", \"javascript\": \"javascriptreact\"}",
-	"emmetVariables": "Variables to be used in emmet snippets"
+	"emmetVariables": "Variables to be used in emmet snippets",
+	"emmetTriggerExpansionOnTab": "When enabled, emmet abbreviations are expanded when pressing TAB."
 }
\ No newline at end of file

extensions/emmet/src/abbreviationActions.ts

@@ -82,17 +82,17 @@ export function wrapIndividualLinesWithAbbreviation(args) {
 
 }
 
-export function expandEmmetAbbreviation(args) {
+export function expandEmmetAbbreviation(args): Thenable<boolean> {
 	const syntax = getSyntaxFromArgs(args);
 	if (!syntax || !validate()) {
-		return Promise.resolve(false);
+		return fallbackTab();
 	}
 
 	const editor = vscode.window.activeTextEditor;
 
 	let rootNode = parseDocument(editor.document);
 	if (!rootNode) {
-		return Promise.resolve(false);
+		return fallbackTab();
 	}
 
 	let abbreviationList: ExpandAbbreviationInput[] = [];
@@ -153,10 +153,18 @@ export function expandEmmetAbbreviation(args) {
 		abbreviationList.push({ syntax, abbreviation, rangeToReplace, filters });
 	});
 
-	return expandAbbreviationInRange(editor, abbreviationList, allAbbreviationsSame);
+	return expandAbbreviationInRange(editor, abbreviationList, allAbbreviationsSame).then(success => {
+		if (!success) {
+			return fallbackTab();
+		}
+	});
 }
 
-
+function fallbackTab(): Thenable<boolean> {
+	if (vscode.workspace.getConfiguration('emmet')['triggerExpansionOnTab'] === true) {
+		return vscode.commands.executeCommand('tab');
+	}
+}
 /**
  * Checks if given position is a valid location to expand emmet abbreviation.
  * Works only on html and css/less/scss syntax
@@ -200,6 +208,7 @@ export function isValidLocationForEmmetAbbreviation(currentNode: Node, syntax: s
  * @param editor
  * @param expandAbbrList
  * @param insertSameSnippet
+ * @returns false if no snippet can be inserted.
  */
 function expandAbbreviationInRange(editor: vscode.TextEditor, expandAbbrList: ExpandAbbreviationInput[], insertSameSnippet: boolean): Thenable<boolean> {
 	if (!expandAbbrList || expandAbbrList.length === 0) {
@@ -217,6 +226,9 @@ function expandAbbreviationInRange(editor: vscode.TextEditor, expandAbbrList: Ex
 				insertPromises.push(editor.insertSnippet(new vscode.SnippetString(expandedText), expandAbbrInput.rangeToReplace));
 			}
 		});
+		if (insertPromises.length === 0) {
+			return Promise.resolve(false);
+		}
 		return Promise.all(insertPromises).then(() => Promise.resolve(true));
 	}
 

src/vs/workbench/parts/emmet/electron-browser/actions/expandAbbreviation.ts

@@ -8,6 +8,8 @@ import nls = require('vs/nls');
 import { EmmetEditorAction } from 'vs/workbench/parts/emmet/electron-browser/emmetActions';
 import { editorAction } from 'vs/editor/common/editorCommonExtensions';
 import { EditorContextKeys } from 'vs/editor/common/editorContextKeys';
+import { KeyCode } from 'vs/base/common/keyCodes';
+import { ContextKeyExpr } from 'vs/platform/contextkey/common/contextkey';
 
 @editorAction
 class ExpandAbbreviationAction extends EmmetEditorAction {
@@ -18,7 +20,15 @@ class ExpandAbbreviationAction extends EmmetEditorAction {
 			label: nls.localize('expandAbbreviationAction', "Emmet: Expand Abbreviation"),
 			alias: 'Emmet: Expand Abbreviation',
 			precondition: EditorContextKeys.writable,
-			actionName: 'expand_abbreviation'
+			actionName: 'expand_abbreviation',
+			kbOpts: {
+				primary: KeyCode.Tab,
+				kbExpr: ContextKeyExpr.and(
+					EditorContextKeys.textFocus,
+					EditorContextKeys.tabDoesNotMoveFocus,
+					ContextKeyExpr.has('config.emmet.triggerExpansionOnTab')
+				)
+			}
 		});
 
 	}