When comparing JSFiddle vs exercism.org, the Slant community recommends exercism.org for most people. In the question“What are the best resources to learn JavaScript?” exercism.org is ranked 3rd while JSFiddle is ranked 17th. The most important reason people chose exercism.org is:
Rather than merely test for code correctness, Exercism uses peer review to improve general programming techniques. Users are encouraged to comment on others' solutions, and refine their own based on feedback.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro CoffeeScript and SCSS support
In addition to supporting JavaScript and CSS, language settings can be switched to CoffeeScript and SCSS.
Pro Allows collaborating on code
JSFiddle makes it easy to save the code snippets and send the link to others who can view and edit the code.
Pro Supports a wide variety of frameworks and extensions
JSFiddle can switch to selection of frameworks and extensions including jQuery, AngularJS, ReactiveJS, D3 simply from a dropdown.
Pro Human review and feedback
Rather than merely test for code correctness, Exercism uses peer review to improve general programming techniques. Users are encouraged to comment on others' solutions, and refine their own based on feedback.
Pro Practice with production tools
Unlike many code practice websites, Exercism requires the user to develop and test entirely offline, submitting only the finished code. This promotes familiarity with essential tools and workflow, not just the bare language.
Cons
Con Not actually an IDE
JSFiddle is not actually an IDE and is only suitable for small blocks of code.
Con Non free/libre (proprietary)
Con Custom commandline client
Exercism requires using a CLI utility to fetch and submit exercises. This is inconvenient compared to web-only alternatives, and poses an additional barrier to entry for some users.