How does a senior developer's code look in comparison to a junior developer?

the code of senior developers is more readable , reusable and follow the general naming conversion and coding principle. 

while the junior developer code is not beautiful as senior do, the problem of structuring the code to the general conversion is seen in the code of junior developer 

Senior devloper is more intended towards generic coding and performance oriented while writing the code.

Junior programmer are more inclined towards fulfilling the functionality required. 

Seniors developer prefers  modular-coding with intention to exceed the quality standards.

Junior developer code to try out-of-the-box !

it will be more structured ,readable , minified  and very streight to the point

Junior: They start out with simple code because they don’t know any better. It takes them a fair amount of time to code things because they’re constantly looking up examples and rewriting.

Senior: Then they see how much work it is to maintain, how under-appreciated their work is, how often their work of art is thrown away, how often they miss deadlines, how quickly fad languages and frameworks come and go, and they settle down into a zen-like balance of good code quality and reasonable speed.

Code looks like it was written by a pessimist.

senior: well structured code. error is handling in comment section and

junior: developer are less focus on error handling and his code is more no of lines

Senior: Well structured code, taking into consideration the memory size when declaring variables and objects, handling all cases for a fuction.All the above in a short code (less lines of code)

Junior: Alot of code lines with extra varables and extra conditions with some sort of mass. 

most importent is error handling and code comment. junior devloper less focus on error handling. senior devloper also provide better comments before code and write code using oops concept.

Follows :

1. Patterns and Structured Objects

2. Understand Object behaviour

3. Keep intend, space and simple comments while code

4. Use test codes

Knows how to think out of the box, very much hands-on and can create solution using different programming