It's universally high for all the types of developers
as there's no area where this profession couldn't cover all the basic human needs. With a previously mentioned salary that is well above the national average, the job satisfaction level also depends on how stressful the job atmosphere is. Luckily, JS pros are very in demand and make up for the second largest group when it comes to being a "hot commodity" on the market: only Java devs have more monthly jobs advertised in the US (11,611 vs. 8,593) that allow for the meticulous choice with a cozy office and nice working conditions. It also relieves a good portion of the stress associated with unemployment periods since they know it won't be hard to find a new job.
Another factor is the price of rent that usually cuts into a good chunk of a devs' income. Funnily enough, San Francisco and New York aren't the dream locations: none of these places will let them earn more than $100K (€88K) a year regardless of their skills, the rental expenses
of $38-40K (€33-35K) a year will somewhat decrease the happiness level. Rentals in cities like Dallas, Seattle, and Chicago will only cost $15-20K (€13-17.5K) a year, let alone European capitals that ask for $10-20K (€9-17.5K), but Kiev
is a clear winner here with only $3.5K (€3K) needed to live in comfort.The satisfaction level is typically lower among junior developers (83%)
and is almost flawless for seniors (more than 97%). Engineers from countries with a relatively low average income level tend to be more satisfied than from a highly-developed countries — 85% against 79% respectfully.