It's added complexity because it's not std lib. Importing an entire module just to accomplish something you could easily do with 1 line of code. I'm not arguing that javascript shouldn't have `startsWith`, just saying there's a large overhead associated for a relatively minor performance increase. Thus going back to the debate about proper engineering. Just my 2 cents, feel free to ignore :)

I prefer writing <heading level 1> instead of <h1> :p