Over 590 examples with explanations: JavaScript and SQL. Over 320 of them are free, and code runs right in the app with the output shown underneath.
An everyday JavaScript reference, from strings and collections to async work and design patterns. Every example comes with an explanation, and most of them run.
• 23 sections: basic types, arrays and collections, classes, files, serialization, functions and arrow expressions, exceptions, regular expressions, async operations, databases, algorithms, design patterns.
• Run in the app: the example actually runs and the output appears under the code. Needs an internet connection.
• What changed in new versions: 10 sections from ES2015 to ES2024, with the old and the new code side by side.
• Keyword and function reference: over 170 articles, open in full, with no daily limit.
• SQL alongside: over 200 queries against a live practice database (JOIN, GROUP BY, subqueries, data types).
• Edit examples and add your own; they stay in the app and are always at hand.
• Search looks inside the code itself, not just the titles: remember a fragment and you will find the example.
• Everything except running works offline. No account needed.
WHAT THE FREE VERSION INCLUDES
12 runs and 12 edits a day; the counter resets every morning. The keyword reference is open without limits. Up to 5 examples of your own.
The full version unlocks every example, lifts the daily limits and raises the run limit to 30 a day. One purchase, no subscription.
Built by a developer for developers. In active development since 2015.
This may strike you as somewhat odd and/or much like probably nothing important.. but this app. Is a really really complicated. I am a small town country girl and I know that you.., whoever you are.. or aren’t.. for that matter of factually ..,, anyway I would have to be an idiot to not believe in things that I couldn’t see because I’m not there yet , and would appreciate knowing this knowledge as well. Everything is up for grabs tonight today tommorow just be careful what you type. An inspiration and an idea to keep up the good work. Man.
Useful for reminders and memorization
Laz-P
I primarily wanted an App that can teach me techniques and tricks in JS. I ended up finding this goldmine of an App. I recommend this to any developer learning JS if they want to sharpen their JS skills.
Developer Response
Thank you very much for your feedback 🤝
Missing ECMAScript Features
HardRockJon
Although interfaces are listed in the table of contents. There actually isn’t any information on them. Instead you get “ //In Javascript there are no interfaces//ECMAScript 6 feature” and then classes examples. The correct way to do this is show interfaces with a note they aren’t a JavaScript feature.
Developer Response
Thank you, I will take into account your comment in the next update of the database 🤝
Great Resource
Neohope22
Just getting started so far, and I love it. Thank you!!I love the way it is structured, helps organize the language and the practice for me.
Developer Response
Thanks for your feedback 👍 I am glad that you liked this app 🤝
• Copying code is open in the free version too, with no limit.
• Supports iOS 17 and macOS 14.
Version 4.07
The developer, Fedor Obraztsov, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Privacy practices may vary, for example, based on the features you use or your age. Learn More
The developer indicated that this app supports the following accessibility features. Learn More
