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JS Class Features - Interactive Sandbox | IconVault

Private fields, private methods, static blocks, getters and setters, inheritance, brand checks. Edit and run each in a sandboxed iframe. Free.

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JS Class Features

Private fields, static blocks, inheritance in a sandbox

5 of 5 free uses left

Private fields

Fields declared with # are truly private: invisible to subclasses, destructuring and JSON.

5 of 5 free runs left.

Console output

No output yet

Press "Run in sandbox". Code executes in an isolated iframe, never touching this page.

Sandbox notes: the runner uses asandbox="allow-scripts" iframe with no Function constructor and no access to your page, cookies or network. Edit the code freely.

About this tool

IconVault's JS Class Features is a hands-on lab for modern JavaScript classes. Six lessons cover private fields and private methods, static initialization blocks, getters and setters with validation, inheritance with super, and the ergonomic brand check pattern, each with editable code and a plain-English explainer.

Press run and your code executes in a sandboxed iframe, completely isolated from the page, with console output shown instantly. Experiment freely: break things, fix them, and build real intuition. Everything is free and runs fully in your browser.

Frequently asked questions

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