The Tor Browser / file revision

 /*

  * For arrow functions, Script.prototype.sourceStart and

  * Script.prototype.sourceLength should comprise the entire function expression

  * (including arguments)

  */

 let g = newGlobal();

 let dbg = new Debugger(g);

 function test(string, ranges) {

     var index = 0;

     dbg.onNewScript = function (script) {

         function traverse(script) {

             script.getChildScripts().forEach(function (script) {

                 assertEq(script.sourceStart, ranges[index][0]);

                 assertEq(script.sourceLength, ranges[index][1]);

                 ++index;

                 traverse(script);

             });

         }

         traverse(script);

     };

     g.eval(string);

     /*

      * In some configurations certain child scripts are listed twice, so we

      * cannot rely on index always having the exact same value

      */

     assertEq(0 < index && index <= ranges.length, true);

 };

 test("() => {}", [[0, 8]]);

 test("(x, y) => { x * y }", [[0, 19]]);

 test("x => x * x", [[0, 10]]);

 test("x => x => x * x", [[0, 15], [5, 10], [5, 10]]);