Front-End Salaries
The national average in the U.S for a mid-level front-end developer is somewhere between $75k and 100k.
Image source: https://www.glassdoor.com/Salaries/front-end-developer-salary-SRCH_KO0,19.htm
Image source: https://www.indeed.com/salaries/Front-End-Developer-Salaries
Of course when you first start expect to enter the field at around 43k depending upon location and portfolio.
NOTES:
A lead/senior front-end developer/engineer can potentially live wherever they want (i.e., work remotely) and make over $150k a year (visit angel.co, sign-up, review front-end jobs over $150k or examine the salary ranges on Stack Overflow Jobs).