@divebell/extension-memory

This Divebell Extension checks whether a repeatable browser journey causes sustained growth in JavaScript memory, DOM nodes, or event listeners. It also exposes lower-level memory metrics, allocation sampling, and heap snapshots for focused investigation.

It works with regular Chrome pages and does not require Runtime SDK, a framework plugin, or build metadata.

Install

divebell extensions add @divebell/extension-memory

Run a complete check

Create a scenario module with a run function that performs one iteration of the target page journey, then run:

divebell memory check \
  --url http://localhost:3000/ \
  --scenario ./scripts/memory-scenario.mjs \
  --warmup 3 \
  --iterations 12 \
  --artifact-dir ./.memory-artifacts

The command owns the browser lifecycle, warmup, repeated operations, metrics, allocation capture, before-and-after heap snapshots, reporting, and cleanup.

It writes:

• report.json;
• allocation.heapprofile;
• baseline.heapsnapshot; and
• final.heapsnapshot.

Focused commands

Inspect the current page after opening it with Divebell:

divebell memory metrics
divebell memory sampling start --sampling-interval 32768
# Perform the page journey.
divebell memory sampling stop /tmp/page.heapprofile --top 20
divebell memory snapshot /tmp/page.heapsnapshot --timeout 120000
divebell memory status
divebell memory cancel

Use a repeated memory check for leak decisions. A single high reading or one temporary peak is not enough evidence of sustained growth.

See the complete memory analysis guide.