It is a long established fact that a reader will be distracted by the readable con tent of a page nomao when loing at its layout. The point of using Ipsum is that it has a more-or-less normal distribution of letters readable content of a page.

The cycle for adding new features, including any refactoring, is roughly this: write failing test; code; get to green; make it right. If you’re doing it right, you’re executing a lot of unit tests along the way, sometimes a focused set and sometimes the entire suite.

While in ES5 ‘this’ referred to the parent of the function, in ES6, arrow functions use lexical scoping — ‘this’ refers to it’s current surrounding scope and no further. Thus the inner function knew to bind to the inner function only, and not to the object’s method.