BDHS seems strictly less powerful than a time travel debugger. You can just set a hardware breakpoint and run backwards until the value is set.
Why not just do proper time travel? Is that absent for Javascript?
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I'm building a JavaScript debugger called Wirebrowser. It combines network inspection, request rewriting, heap snapshots, and live object search.
The main experimental feature is BDHS (Breakpoint-Driven Heap Search): it hooks into the JavaScript debugger and automatically captures a heap snapshot at every pause and performs a targeted search for the value or structure of interest. This reveals the moment a value appears in memory and the user-land function responsible for creating it.
Another interesting feature is the Live Object Search: it inspects runtime objects (not just snapshots), supports regex and object similarity, and lets you patch objects directly at runtime.
Whitepaper: https://fcavallarin.github.io/wirebrowser/BDHS-Origin-Trace
Feedback very welcome, especially on whether BDHS would help your debugging workflow.
The browser’s debugging API (CDP) also doesn’t provide a way to capture or rewind engine state without modifying the application.
BDHS works within the constraints of zero instrumentation: it relies only on Debugger.paused and heap snapshots, so it can trace where a value originates without altering the code being debugged.