[vbezhenar]

The problem is that you need one function and you're pulling an entire library. Also you have some limited use-case (e.g. you don't have to support IE 6), but libraries tend to accumulate all the cruft in the world over the years, so you're pulling and executing lots of unnecessary code. JavaScript is too dynamic to reliably delete unused code, so even approaches like tree shaking, etc do not work well. And left-pad style libraries has its own problems, yeah.

There are universal utility libraries. jQuery for DOM, underscore for general utilities. It's OK to use them, because everyone knows them. But if you miss some tiny function, just write it yourself. DRY principle often brings more harm than good.

[pojzon]

I would argue whether DRY enforces 3rd party libraries usage. "Yourself" touches the code you wrote, noone asks you to use already written solutions.