support generator functions (#4620)

test/mocha/yields.js

@@ -0,0 +1,82 @@
+var assert = require("assert");
+var UglifyJS = require("../node");
+
+describe("generator", function() {
+    it("Should reject `yield` as symbol name within generator functions only", function() {
+        [
+            "function yield() {}",
+            "function(yield) {}",
+            "function() { yield:{} }",
+            "function() { var yield; }",
+            "function() { function yield() {} }",
+            "function() { try {} catch (yield) {} }",
+        ].forEach(function(code) {
+            var ast = UglifyJS.parse("(" + code + ")();");
+            assert.strictEqual(ast.TYPE, "Toplevel");
+            assert.strictEqual(ast.body.length, 1);
+            assert.strictEqual(ast.body[0].TYPE, "SimpleStatement");
+            assert.strictEqual(ast.body[0].body.TYPE, "Call");
+            assert.strictEqual(ast.body[0].body.expression.TYPE, "Function");
+            assert.throws(function() {
+                UglifyJS.parse("(" + code.replace(/^function/, "function*") + ")();");
+            }, function(e) {
+                return e instanceof UglifyJS.JS_Parse_Error;
+            }, code);
+        });
+    });
+    it("Should reject `yield` expression outside of generator functions", function() {
+        [
+            "yield 42;",
+            "function f() { yield 42; }",
+            "function* f() { function g() { yield 42; } }",
+        ].forEach(function(code) {
+            assert.throws(function() {
+                UglifyJS.parse(code);
+            }, function(e) {
+                return e instanceof UglifyJS.JS_Parse_Error;
+            }, code);
+        });
+    });
+    it("Should reject `yield` expression directly on computed key of function argument", function() {
+        [
+            "function f({ [yield 42]: a }) {}",
+            "function* f({ [yield 42]: a }) {}",
+        ].forEach(function(code) {
+            assert.throws(function() {
+                UglifyJS.parse(code);
+            }, function(e) {
+                return e instanceof UglifyJS.JS_Parse_Error;
+            }, code);
+        });
+    });
+    it("Should accept `yield` expression nested within computed key of function argument", function() {
+        [
+            "function f({ [function*() { yield 42; }()]: a }) {}",
+            "function* f({ [function*() { yield 42; }()]: a }) {}",
+        ].forEach(function(code) {
+            var ast = UglifyJS.parse(code);
+            assert.strictEqual(ast.TYPE, "Toplevel");
+            assert.strictEqual(ast.body.length, 1);
+            assert.strictEqual(ast.body[0].argnames.length, 1);
+            assert.strictEqual(ast.body[0].argnames[0].TYPE, "DestructuredObject");
+        });
+    });
+    it("Should reject `yield*` without an expression", function() {
+        [
+            "yield*",
+            "yield*;",
+            "yield*,",
+            "(yield*)",
+            "[ yield* ]",
+            "42[yield*]",
+            "yield* && 42",
+        ].forEach(function(code) {
+            code = "function* f() { " + code + " }";
+            assert.throws(function() {
+                UglifyJS.parse(code);
+            }, function(e) {
+                return e instanceof UglifyJS.JS_Parse_Error;
+            }, code);
+        });
+    });
+});