s3c

A JavaScript editor with code evaluation. Built for beginner JS students, useful for all. Try it.

Features

• Inline code evaluation via a web worker
• Linting via ESLint
• Content backup in local storage
• Editing features via CodeMirror

Caveat

This editor is mainly intended for writing and evaluating small snippets of JavaScript code. Do not rely solely on local storage for safekeeping, as the size limit varies from browser to browser.

Code evaluation uses eval, but is sandboxed in a web worker (so you cannot interfere with the editor by redefining, say, Object.prototype). The evaluation timeouts after 1 second, outputting a ⌛.

Be aware that in a web worker, the identifier self is bound to the global object, but window and document are undefined.

Acknowledgments

Marijn Haverbeke and all the contributors for CodeMirror. Nicholas C. Zakas and contributors for ESLint. Jonathan for the initial idea, feedback and improvements. My students for testing.