I work in a contract position and reviewed the code of a senior engineer recently. Regretfully I can't provide context to preserve anonymity.

He wrote awful JavaScript;

- handled a single DOM element with 2 different frontend libraries
- used the logical operator && to 'chain' two methods (it didn't work) instead of returning a boolean value,
- broke everything down into minute detail (a comment box had 7 components!),
- API calls were made for every component update instead of maintaining local component state where it made sense, which meant UI updates were slow,
- animated EVERYTHING, which made my Firefox on Xubuntu i7 64bit with 16GB RAM beg for mercy.

I had a rough couple of months with interviews, with 2nd stage technical interviewers throwing impossible tasks at me.

Example:

1. Create an online Python code editor with Javascript which can compile Python bytecode,
2. Use Mesos and Kafka to create real time architecture for Tensorflow with a Javascript frontend in 1 day. (I asked, and wasn't allowed to use Kubernetes or serverless architecture),
3. Hack a website from the browser's address bar using parameters ( what?!! ),

Obviously, the next time I meet a 'senior', I'm going to tell him talk is cheap;

'SHOW ME YOUR CODE.'