粗糙的es6 -> es5转换正则集

(r'() => {}','function () {return {}}'),

# (r'{...(.+?)}','Object.assign({}, \1)') ,
# (r'(let|const) ', 'var '),
# (r'(w+) () {', '\1: function () {'),
# (r'(s*)for (var (w+) of ([w.]+)) {', r'1for (var i=0; i < 3.length; i++) {1  var 2 = 3[i]')