[FEATURE] Support ES2021 language features

By upgrading espree to the latest version, ES2021 language features
are now supported.

lib/lbt/analyzer/JSModuleAnalyzer.js

@@ -64,6 +64,7 @@ const EnrichedVisitorKeys = (function() {
 		BreakStatement: [],
 		CallExpression: [], // special handling
 		CatchClause: ["param", "body"],
+		ChainExpression: [],
 		ClassBody: [],
 		ClassDeclaration: [],
 		ClassExpression: [],
@@ -125,15 +126,18 @@ const EnrichedVisitorKeys = (function() {
 		 * All properties in an object pattern are executed.
 		 */
 		ObjectPattern: [], // properties
+		// PrivateIdentifier: [], // will come with ES2022
 		Program: [],
 		Property: [],
+		// PropertyDefinition: [], // will come with ES2022
 		/*
 		 * argument of the rest element is always executed under the same condition as the rest element itself
 		 */
 		RestElement: [], // argument
 		ReturnStatement: [],
 		SequenceExpression: [],
 		SpreadElement: [], // the argument of the spread operator always needs to be evaluated - argument
+		// StaticBlock: [], // will come with ES2022
 		Super: [],
 		SwitchStatement: [],
 		SwitchCase: ["test", "consequent"], // test and consequent are executed only conditionally
@@ -174,6 +178,9 @@ const EnrichedVisitorKeys = (function() {
 		// Check if the visitor-key exists in the available Syntax because
 		// the list of visitor-keys does not match the available Syntax.
 		if (!Syntax[type]) {
+			// Deprecated / removed:
+			// ExperimentalRestProperty
+			// ExperimentalSpreadProperty
 			return;
 		}
 		// Ignore JSX visitor-keys because they aren't used.

lib/lbt/utils/parseUtils.js

@@ -9,7 +9,7 @@ function parseJS(code, userOptions = {}) {
 	// allowed options and their defaults
 	const options = {
 		comment: false,
-		ecmaVersion: 2020,
+		ecmaVersion: 2021,
 		range: false,
 		sourceType: "script",
 	};

package.json

@@ -109,7 +109,7 @@
 		"cheerio": "1.0.0-rc.9",
 		"escape-unicode": "^0.2.0",
 		"escope": "^3.6.0",
-		"espree": "^6.2.1",
+		"espree": "^9.3.0",
 		"globby": "^11.1.0",
 		"graceful-fs": "^4.2.9",
 		"jsdoc": "^3.6.7",

test/fixtures/lbt/modules/es6-syntax.js

@@ -40,4 +40,9 @@ sap.ui.define([
 		await Promise.resolve();
 	};
 
+	// chain expression
+	if (m1?.foo?.bar) {
+		sap.ui.require(["conditional/module4"]);
+	}
+
 });

test/lib/lbt/analyzer/JSModuleAnalyzer.js

@@ -493,6 +493,7 @@ test("ES6 Syntax", (t) => {
 			"conditional/module1.js",
 			"conditional/module2.js",
 			"conditional/module3.js",
+			"conditional/module4.js",
 			"static/module1.js",
 			"static/module2.js",
 			"static/module3.js",

test/lib/lbt/utils/parseUtils.js

@@ -18,3 +18,9 @@ test("successful parse step", (t) => {
 	t.true(ast != null && typeof ast === "object");
 	t.is(ast.type, "Program");
 });
+
+test("successful parse step (ES2021 features)", (t) => {
+	const ast = parseJS("const x = 1_000_000_000;"); // numeric separators
+	t.true(ast != null && typeof ast === "object");
+	t.is(ast.type, "Program");
+});