feat: expose the v8 flags with our node introspection mechanism

Author: art049

packages/core/src/index.ts

@@ -1,4 +1,36 @@
+import { writeFileSync } from "fs";
 import path from "path";
+
+const getV8Flags = (nodeVersionMajor: number) => {
+  const flags = [
+    "--hash-seed=1",
+    "--random-seed=1",
+    "--no-opt",
+    "--predictable",
+    "--predictable-gc-schedule",
+  ];
+  if (nodeVersionMajor < 18) {
+    flags.push("--no-randomize-hashes");
+  }
+  if (nodeVersionMajor < 20) {
+    flags.push("--no-scavenge-task");
+  }
+  return flags;
+};
+
+if (process.env.__CODSPEED_NODE_CORE_INTROSPECTION_PATH__ !== undefined) {
+  const nodeVersionMajor = parseInt(process.version.slice(1).split(".")[0]);
+
+  const introspectionMetadata = {
+    flags: getV8Flags(nodeVersionMajor),
+  };
+  writeFileSync(
+    process.env.__CODSPEED_NODE_CORE_INTROSPECTION_PATH__,
+    JSON.stringify(introspectionMetadata)
+  );
+  process.exit(0);
+}
+
 declare const __VERSION__: string;
 
 /* eslint-disable @typescript-eslint/no-empty-function */