Live JavaScript Editor
web2026·Full Stack Engineer
A browser-based code editor with line numbers, monospace font rendering, and sandboxed JavaScript execution. Write any JS code, hit Run, and see console output instantly — all without leaving the page. Includes a pre-loaded Fibonacci demo.
JavaScriptReactSandboxed Function ConstructorTypeScript
The Challenge
Executing arbitrary user-written JavaScript safely in the browser without security vulnerabilities, infinite loop crashes, or global scope pollution.
The Approach
Built a sandboxed execution environment using the Function constructor with a custom-mocked console object that captures all log/warn/error output streams. The global scope is never exposed.
The Result
A lightweight, safe code playground that executes JavaScript instantly with full console output capture — used for live coding demos.