correctly parse export of function & class (#2135)

lib/parse.js

@@ -2413,72 +2413,60 @@ function parse($TEXT, options) {
     function export_() {
         var start = S.token;
         var is_default;
-        var exported_value;
-        var exported_definition;
         var exported_names;
 
         if (is("keyword", "default")) {
             is_default = true;
             next();
-        } else {
+        } else if (exported_names = map_names(false)) {
-            exported_names = map_names(false);
+            if (is("name", "from")) {
+                next();
 
-            if (exported_names) {
+                var mod_str = S.token;
-                if (is("name", "from")) {
+                if (mod_str.type !== 'string') {
-                    next();
+                    unexpected();
-
-                    var mod_str = S.token;
-                    if (mod_str.type !== 'string') {
-                        unexpected();
-                    }
-                    next();
-
-                    return new AST_Export({
-                        start: start,
-                        is_default: is_default,
-                        exported_names: exported_names,
-                        module_name: new AST_String({
-                            start: mod_str,
-                            value: mod_str.value,
-                            quote: mod_str.quote,
-                            end: mod_str,
-                        }),
-                        end: prev(),
-                    });
-                } else {
-                    return new AST_Export({
-                        start: start,
-                        is_default: is_default,
-                        exported_names: exported_names,
-                        end: prev(),
-                    });
                 }
+                next();
+
+                return new AST_Export({
+                    start: start,
+                    is_default: is_default,
+                    exported_names: exported_names,
+                    module_name: new AST_String({
+                        start: mod_str,
+                        value: mod_str.value,
+                        quote: mod_str.quote,
+                        end: mod_str,
+                    }),
+                    end: prev(),
+                });
+            } else {
+                return new AST_Export({
+                    start: start,
+                    is_default: is_default,
+                    exported_names: exported_names,
+                    end: prev(),
+                });
             }
         }
 
-        var is_definition = is("keyword", "var") || is("keyword", "let") || is("keyword", "const");
+        var node;
-        if (is_definition) {
+        var exported_value;
-            if (is_default) unexpected();
+        var exported_definition;
-            exported_definition = statement();
+        if (is("punc", "{")
-        } else if (is("keyword", "class")) {
+            || is_default
-            var cls = expr_atom(false);
+                && (is("keyword", "class") || is("keyword", "function"))
-            if (cls.name) {
+                && is_token(peek(), "punc")) {
-                cls.name = new AST_SymbolDefClass(cls.name);
-                exported_definition = new AST_DefClass(cls);
-            } else {
-                exported_value = cls;
-            }
-        } else if (is("keyword", "function")) {
-            var func = expr_atom(false);
-            if (func.name) {
-                func.name = new AST_SymbolDefun(func.name);
-                exported_definition = new AST_Defun(func);
-            } else {
-                exported_value = func;
-            }
-        } else {
             exported_value = expression(false);
             semicolon();
+        } else if ((node = statement()) instanceof AST_Definitions && is_default) {
+            unexpected(node.start);
+        } else if (node instanceof AST_Definitions || node instanceof AST_Defun || node instanceof AST_DefClass) {
+            exported_definition = node;
+        } else if (node instanceof AST_SimpleStatement) {
+            exported_value = node.body;
+        } else {
+            unexpected(node.start);
         }
 
         return new AST_Export({

test/compress/export.js

@@ -107,3 +107,16 @@ issue_2129: {
         export const { keys } = Object;
     }
 }
+
+async_func: {
+    options = {
+        keep_fargs: false,
+        unused: true,
+    }
+    input: {
+        export async function Foo(x){};
+    }
+    expect: {
+        export async function Foo(){};
+    }
+}

test/input/invalid/export_2.js

@@ -0,0 +1 @@
+export class{};

test/input/invalid/export_3.js

@@ -0,0 +1 @@
+export function(){};

test/mocha/cli.js

@@ -534,13 +534,13 @@ describe("bin/uglifyjs", function () {
         });
     });
     it("Should throw syntax error (block-level export)", function(done) {
-        var command = uglifyjscmd + ' test/input/invalid/export.js -m';
+        var command = uglifyjscmd + ' test/input/invalid/export_1.js -m';
 
         exec(command, function (err, stdout, stderr) {
             assert.ok(err);
             assert.strictEqual(stdout, "");
             assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
-                "Parse error at test/input/invalid/export.js:2,4",
+                "Parse error at test/input/invalid/export_1.js:2,4",
                 "    export var V = 1;",
                 "    ^",
                 "ERROR: Export statement may only appear at top level"
@@ -563,6 +563,36 @@ describe("bin/uglifyjs", function () {
             done();
         });
     });
+    it("Should throw syntax error (anonymous class)", function(done) {
+        var command = uglifyjscmd + ' test/input/invalid/export_2.js';
+
+        exec(command, function (err, stdout, stderr) {
+            assert.ok(err);
+            assert.strictEqual(stdout, "");
+            assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+                "Parse error at test/input/invalid/export_2.js:1,12",
+                "export class{};",
+                "            ^",
+                "ERROR: Unexpected token: punc ({)"
+            ].join("\n"));
+            done();
+        });
+    });
+    it("Should throw syntax error (anonymous function)", function(done) {
+        var command = uglifyjscmd + ' test/input/invalid/export_3.js';
+
+        exec(command, function (err, stdout, stderr) {
+            assert.ok(err);
+            assert.strictEqual(stdout, "");
+            assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+                "Parse error at test/input/invalid/export_3.js:1,15",
+                "export function(){};",
+                "               ^",
+                "ERROR: Unexpected token: punc (()"
+            ].join("\n"));
+            done();
+        });
+    });
     it("Should handle literal string as source map input", function(done) {
         var command = [
             uglifyjscmd,