Earlier quoted context omitted.
Anyone who claims to know JS and doesn't have "this" down cold is either a disaster waiting to happen, or a disaster in progress.
Now, hold on there. These "anyone who" statements chafe me; like the junior dev who exclaimed "anyone who doesn't write unit tests shouldn't call themselves an engineer" in a meeting filled with people 15 years his senior who had collectively shipped far, far more successful software than him, without writing tests. Several years ago, I led two different front-end web teams at a large, well-known company. I wrote a l…
The ECMAScript committe are taking steps to make "this" more useful, but the current semantic is so insane that I don't it's particularly surprising that people who aren't language lawyers don't understand it.
(*) Given that Javascript uses a single-threaded model.