Fixing problems at the source

Get rid of runtime errors in the cloud with JavaScript Studio

Jane Elizabeth
JavaScript Studio
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Looking for a brand new way to find runtime errors? JavaScript Studio is now generally available on GitHub! Evaluate your source code in a custom runtime.

It’s here! After several months of testing in a private beta, JavaScript Studio is now generally available on GitHub for anyone to try for free!

JavaScript Studio is a cloud service that finds errors in JavaScript programs by dynamically evaluating the source code in a custom runtime. The brainchild of Maximilian Antoni, this cloud service is intended to find runtime errors by evaluating the source code and highlight errors or thrown exceptions.

How does JavaScript Studio work?

Basically, JavaScript Studio acts as an analyzer. It parses your source code into an AST, which it evaluates dynamically and tries to reach every possible execution branch. If a global entry point is specified, every exposed function will be evaluated, including functions that are returned by other functions. This allows JavaScript Studio to automatically scan the entire API of a library.

Essentially, JavaScript Studio looks for runtime errors like invalid function calls or wrong types being used.

SEE MORE: The ultimate JavaScript plugin cheat sheet

Every runtime creates an individual report. This report crunches the numbers and breaks down the number of unique AST nodes and exposed functions analyzed. These error reports are pretty useful. They go over every error with a message, a code snipped highlighting the source location where the error occurred, a stack trace and a list of involved variables and their values.

This cloud service is available online through the JavaScript Studio website and via a command line tool. Since it is still in the early access phase, you need to upload the source code with the command line tool. However, you can review your build history the website.


If you keep it simple, JavaScript Studio is free. The free option allows encrypted uploads for privacy concerns and goes all the way up to 500,000 AST nodes a month. For those of us with a lot of code to check, there’s a paid subscription level.


Jane Elizabeth
Jane Elizabeth is an assistant editor for

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