That built-in experience comes via vscode-js-debug, a GitHub project described as a Debugger Adapter Protocol -based JavaScript debugger that works with Node.js, Chrome, Edge, WebView2 and VS Code ...

Microsoft's code editor Visual Studio Code now ships with a built-in Javascript debugger.

In VS Code 1.66, the JavaScript debugger now supports collecting and visualizing heap profiles, so developers can see where and how much memory is being allocated over time.