Compare perf of nyc pre-instrumentation vs c8

nyc-run.config.js

@@ -0,0 +1,12 @@
+module.exports = {
+  all: true,
+  include: ['tests/node_modules/ts-node/**'],
+  exclude: ['**/*.d.ts', 'tests/node_modules/ts-node/node_modules/**'],
+  extension: [],
+  instrument: false,
+  'hook-require': false,
+  'hook-run-in-context': false,
+  'hook-run-in-this-context': false,
+  excludeNodeModules: false,
+  excludeAfterRemap: false,
+};

package.json

@@ -68,10 +68,12 @@
     "build-configSchema": "typescript-json-schema --topRef --refs --validationKeywords allOf --out tsconfig.schema.json tsconfig.build-schema.json TsConfigSchema && node --require ./register ./scripts/create-merged-schema",
     "build-pack": "node ./scripts/build-pack.js",
     "test-spec": "ava",
-    "test-cov": "nyc ava",
+    "test-instrument": "nyc instrument --in-place ./tests/node_modules/ts-node",
+    "test-cov": "nyc --nycrc-path ./nyc-run.config.js ava",
     "test": "npm run build && npm run lint && npm run test-cov --",
     "test-local": "npm run lint-fix && npm run build-tsc && npm run build-pack && npm run test-spec --",
     "pre-debug": "npm run build-tsc && npm run build-pack",
+    "coverage-summary": "nyc report",
     "coverage-report": "nyc report --reporter=lcov",
     "prepare": "npm run clean && npm run build-nopack",
     "api-extractor": "api-extractor run --local --verbose",

src/test/helpers.ts

@@ -122,6 +122,9 @@ export async function installTsNode() {
       try {
         rimrafSync(join(TEST_DIR, 'node_modules'));
         await promisify(childProcessExec)(`npm install`, { cwd: TEST_DIR });
+        await promisify(childProcessExec)(`npm run test-instrument`, {
+          cwd: ROOT_DIR,
+        });
         const packageLockPath = join(TEST_DIR, 'package-lock.json');
         existsSync(packageLockPath) && unlinkSync(packageLockPath);
         break;