How much of javascript should I know to land a job ?

Question

and also can you guys give me examples web apps I can build to improve my js?

Answer 1

Landing a job depends more than coding skills. The ability to understand how a code or app works, why it has written that way and how to implement your own solution are key skills. Being a developer is not about knowing every language or syntax, it is about having a programming way of thinking and that comes with a lot of practice.
I would recommend to focus on bare javascript followed by functional programming approaches such as typescript/angular 2, which will be wildly popular in the following years both for web and hybrid applications.