Source Map Performance Demo

This project is a simple experiment to get a general sense of the correctness and performance penalty incurred for enabling source map support in a node runtime using various techniques.

The approach taken is to generate builds of a simple application using both esbuild and tsc. The application imports a few commonly used libraries to intentionally inflate the resulting source maps. We then generate N number of stack traces, and record the elapsed time.

• index.ts - simple test app to generate stacks and test their correctness
• run-tests.ts - run timing tests for combinations of node version, compiler, and sourcemap support options.

Related Discussions:

• nodejs/node#41541
• nodejs/node#42417
• evanw/node-source-map-support#122

Usage

Requirements:

• Node v14+
• Docker
• yarn

To run the full suite of tests in docker and capture a table of benchmark results:

# install deps
yarn

# build
yarn clean && yarn build

# run tests
yarn test

To run locally and investigate differences in stack traces:

yarn clean && yarn build:ts
yarn run-tests-locally

Exit code will always be zero, but it will log an object describing each test.

Missing Tests

Items still not verified by this test:

• modules with file URIs should source-map to file URIs, not native paths

Example Output

Results for 10000 stack traces.

node	compiler	options	stack_traces_correct	elapsed_ms
16.20.2	esbuild	--enable-source-maps	❌	235261
16.20.2	esbuild	-r @cspotcode/source-map-support/register	✅	579
16.20.2	esbuild	-r source-map-support/register	❌	574
16.20.2	esbuild			160
16.20.2	tsc	--enable-source-maps	❌	1352
16.20.2	tsc	-r @cspotcode/source-map-support/register	✅	559
16.20.2	tsc	-r source-map-support/register	❌	449
16.20.2	tsc			199
17.9.1	esbuild	--enable-source-maps	❌	240502
17.9.1	esbuild	-r @cspotcode/source-map-support/register	✅	580
17.9.1	esbuild	-r source-map-support/register	❌	539
17.9.1	esbuild			158
17.9.1	tsc	--enable-source-maps	❌	1358
17.9.1	tsc	-r @cspotcode/source-map-support/register	✅	564
17.9.1	tsc	-r source-map-support/register	❌	453
17.9.1	tsc			190
18.17.1	esbuild	--enable-source-maps	❌	243588
18.17.1	esbuild	-r @cspotcode/source-map-support/register	✅	498
18.17.1	esbuild	-r source-map-support/register	❌	533
18.17.1	esbuild			152
18.17.1	tsc	--enable-source-maps	❌	832
18.17.1	tsc	-r @cspotcode/source-map-support/register	✅	473
18.17.1	tsc	-r source-map-support/register	❌	428
18.17.1	tsc			193
19.9.0	esbuild	--enable-source-maps	❌	326
19.9.0	esbuild	-r @cspotcode/source-map-support/register	✅	521
19.9.0	esbuild	-r source-map-support/register	❌	525
19.9.0	esbuild			155
19.9.0	tsc	--enable-source-maps	❌	296
19.9.0	tsc	-r @cspotcode/source-map-support/register	✅	499
19.9.0	tsc	-r source-map-support/register	❌	419
19.9.0	tsc			188
20.5.1	esbuild	--enable-source-maps	❌	419
20.5.1	esbuild	-r @cspotcode/source-map-support/register	✅	454
20.5.1	esbuild	-r source-map-support/register	❌	483
20.5.1	esbuild			141
20.5.1	tsc	--enable-source-maps	❌	336
20.5.1	tsc	-r @cspotcode/source-map-support/register	✅	438
20.5.1	tsc	-r source-map-support/register	❌	384
20.5.1	tsc			173