V8 Map Explorer

Drag and drop a v8.log file into this area, or click to choose from disk.





Search Map by Address

Selected Map


Visualize Map trees that have been gathered using path/to/d8 $FILE --trace-maps.

You can inspect the transition tree in DevTools by looking at document.state.timeline.values.

Keyboard Shortcuts

SHIFT + Arrow Up
Follow Map transition forward (first child)
SHIFT + Arrow Down
Follow Map transition backwards
Arrow Up
Go to previous Map chunk
Arrow Down
Go to next Map in chunk
Arrow Left
Go to previous chunk
Arrow Right
Go to next chunk
Timeline zoom in
Timeline zoom out