ts-memory-baseline

name	ts-memory-baseline
description	Measure and compare TypeScript memory usage for @regle/core and test typechecks. Use when checking TS server pressure, type-level perf regressions, or before/after heavy generic typing changes.
metadata	{"author":"regle","version":"2026.03.19"}

TypeScript memory baseline procedure

This skill defines a reproducible process to measure TypeScript memory usage in this repository.

Hard requirements

1. Use Node 24 for all measurements.
2. Run pnpm build before any test-related measurement.
3. pnpm run test:typecheck should never fail. If it fails, treat the run as invalid for regression tracking.

Environment setup

PATH="/Users/victorgarcia/.nvm/versions/node/v24.15.0/bin:$PATH"
node -v
pnpm -v

Expected:

• Node v24.x
• pnpm 11.20.0 (or project-compatible version)

Measurement runbook (must follow)

1. Ensure no extra monorepo tasks are running.
2. Use the exact Node 24 PATH prefix in every command.
3. Run one warm-up pass that is discarded.
4. Run 3 measured passes and compare medians.
5. Save only the final medians in tests/TS_MEMORY_BASELINE_RESULTS.md.

Measurement commands

A. @regle/core compiler diagnostics

PATH="/Users/victorgarcia/.nvm/versions/node/v24.15.0/bin:$PATH" \
./node_modules/.bin/tsc -p "packages/core/tsconfig.json" --noEmit --extendedDiagnostics

Capture:

• Memory used
• Instantiations
• Check time

B. Full type tests memory

Run build first:

PATH="/Users/victorgarcia/.nvm/versions/node/v24.15.0/bin:$PATH" pnpm build

Then:

PATH="/Users/victorgarcia/.nvm/versions/node/v24.15.0/bin:$PATH" \
/usr/bin/time -l pnpm run test:typecheck

Capture:

• exit code (must be 0)
• maximum resident set size
• peak memory footprint
• real/user/sys

Recommended sequence:

# warm-up (discard)
PATH="/Users/victorgarcia/.nvm/versions/node/v24.15.0/bin:$PATH" \
/usr/bin/time -l corepack pnpm run test:typecheck

# measured runs (collect all 3)
PATH="/Users/victorgarcia/.nvm/versions/node/v24.15.0/bin:$PATH" \
/usr/bin/time -l corepack pnpm run test:typecheck
PATH="/Users/victorgarcia/.nvm/versions/node/v24.15.0/bin:$PATH" \
/usr/bin/time -l corepack pnpm run test:typecheck
PATH="/Users/victorgarcia/.nvm/versions/node/v24.15.0/bin:$PATH" \
/usr/bin/time -l corepack pnpm run test:typecheck

Comparison protocol

Use median deltas because absolute values can vary with machine/CPU load.

1. Compute medians for old baseline and new run.
2. Compute delta % = (new - old) / old * 100.
3. Evaluate with these thresholds:
   • Likely noise: within ±5% for memory metrics.
   • Watch zone: >5% and <=10% increase.
   • Regression candidate: >10% increase.
4. For Check time and real time, treat as noisy:
   • investigate only if increase is >15% and reproducible across runs.
5. If pnpm run test:typecheck exit code is non-zero, invalidate the run (do not update baseline).

Results storage

Store only numeric outcomes in:

• tests/TS_MEMORY_BASELINE_RESULTS.md

Do not put procedural instructions in the results file.