MongoDB Documentation, Release 3.0.4 • XMLList() • isXMLName() Destructuring Assignment V8 does not support the non-standard destructuring assignments. Destructuring assign- ment “extract[s] data from arrays or objects using a syntax that mirrors the construction of array and object literals.” - Mozilla docs 806 The following destructuring assignment is invalid with V8 and throws a SyntaxError : Iterator() , StopIteration() , and Generators V8 does not support Iterator(), StopIteration(), and gener- ators$^{807}$. InternalError() V8 does not support InternalError() . Use Error() instead. for each...in Construct V8 does not support the use of for each...in 808 construct. Use for (var x in y) construct instead. The following for each (var x in y) construct is invalid with V8: Instead, in version 2.4, you can use the for (var x in y) construct: You can also use the array instance method forEach() with the ES5 method Object.keys() : var o = { name: 'MongoDB', version: 2.4 }; for each ( var value in o) { print(value); } var o = { name: 'MongoDB', version: 2.4 }; for ( var prop in o) { var value = o[prop]; print(value); } Object.keys(o).forEach( function (key) { var value = o[key]; print(value); }); original = [4, 8, 15]; var [b, ,c] = a; // <== destructuring assignment print(b) // 4 print(c) // 15 Example Example $^{806}$https://developer.mozilla.org/en-US/docs/JavaScript/New_in_JavaScript/1.7#Destructuring_assignment_(Merge_into_own_page.2Fsection) $^{807}$https://developer.mozilla.org/en-US/docs/JavaScript/Guide/Iterators_and_Generators $^{808}$https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Statements/for_each...in 887 12.2. Previous Stable Releases