Test default values in destructuring patterns: https://people.mozilla.org/~jorendorff/es6-draft.html#sec-destructuring-binding-patterns On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS 40,40 PASS 40,40 PASS 100,100 PASS Hello,Hello PASS 20,20 PASS 30,30 PASS Hello,Hello PASS 20,20 PASS 30,30 PASS z,z PASS zz,zz PASS 40,40 PASS 50,50 PASS 40,40 PASS 50,50 PASS 100,100 PASS null,null PASS false,false PASS 0,0 PASS 50,50 PASS 51,51 PASS 51,51 PASS 52,52 PASS undefined,undefined PASS undefined,undefined PASS 10,10 PASS 30,30 PASS 120,120 PASS 3628800,3628800 PASS 1,1 PASS successfullyParsed is true TEST COMPLETE