Question

is it possible to use string as path ?

instead of _parent._parent.myVar=123;

use something like this:

var path = '_parent._parent';

and then use it as

path.myVar=123';

Answer 1

You may use multiple [].

for your example, you need _parent._parent:

var path = '_parent';
this[path][path].myVar = 123;

another example:

var path1 = '_parent';
var path2 = 'apple';
this[path1][path2].myVar = 456;
//equals to _parent.apple.myVar = 456;