Fix class expressions with heritage in arrow functions

Closes #150.

src/program/types/ClassExpression.js

@@ -28,22 +28,19 @@ export default class ClassExpression extends Node {
 			if (this.superClass) {
 				code.remove(this.start, this.superClass.start);
 				code.remove(this.superClass.end, this.body.start);
-				code.appendLeft(this.start, `/*@__PURE__*/(function (${superName}) {\n${i1}`);
+				code.appendRight(this.start, `/*@__PURE__*/(function (${superName}) {\n${i1}`);
 			} else {
 				code.overwrite(this.start, this.body.start, `/*@__PURE__*/(function () {\n${i1}`);
 			}
 
 			this.body.transpile(code, transforms, true, superName);
 
-			const outro = `\n\n${i1}return ${this.name};\n${i0}}(`;
-
+			let superClass = '';
 			if (this.superClass) {
-				code.appendLeft(this.end, outro);
-				code.move(this.superClass.start, this.superClass.end, this.end);
-				code.prependRight(this.end, '))');
-			} else {
-				code.appendLeft(this.end, `\n\n${i1}return ${this.name};\n${i0}}())`);
+				superClass = code.slice(this.superClass.start, this.superClass.end);
+				code.remove(this.superClass.start, this.superClass.end);
 			}
+			code.appendLeft(this.end, `\n\n${i1}return ${this.name};\n${i0}}(${superClass}))`);
 		} else {
 			this.body.transpile(code, transforms, false);
 		}

test/samples/classes.js

@@ -1226,6 +1226,28 @@ module.exports = [
 			X.prototype.foo = function foo$1 () { return foo };
 			X.prototype.bar = function bar () {};
 		`
+	},
+
+	{
+		description: "transpiles class with super class in arrow function (#150)",
+
+		input: `
+			const f = (b) => class a extends b {};
+		`,
+
+		output: `
+			var f = function (b) { return /*@__PURE__*/(function (b) {
+					function a () {
+						b.apply(this, arguments);
+					}if ( b ) a.__proto__ = b;
+					a.prototype = Object.create( b && b.prototype );
+					a.prototype.constructor = a;
+
+					
+
+					return a;
+				}(b)); };
+		`
 	}
 
 	// TODO more tests. e.g. getters and setters.