fix(core): performance improvements

.vscode/settings.json

@@ -7,5 +7,6 @@
     "Scrapybara"
   ],
   "typescript.tsdk": "node_modules/typescript/lib",
-  "python.languageServer": "None"
+  "python.languageServer": "None",
+  "deno.enable": false
 }

internal/bench/package.json

@@ -11,11 +11,14 @@
   "main": "index.js",
   "license": "MIT",
   "dependencies": {
+    "@langchain/core": "^1.1.24",
     "@langchain/langgraph": "workspace:*",
+    "@langchain/langgraph-checkpoint": "workspace:*",
     "@tsconfig/recommended": "^1.0.2",
     "@types/node": "^18.15.11",
     "prettier": "^2.8.3",
     "typescript": "^4.9.5 || ^5.4.5",
+    "uuid": "^13.0.0",
     "vitest": "^3.2.4"
   }
 }

libs/langgraph-core/package.json

@@ -22,6 +22,7 @@
     "lint": "pnpm lint:eslint && pnpm lint:dpdm",
     "lint:fix": "pnpm lint:eslint --fix && pnpm lint:dpdm",
     "prepublish": "pnpm build",
+    "perf:analyze": "ENABLE_PERFORMANCE_ANALYSIS=true vitest run",
     "test": "vitest run",
     "test:browser": "vitest run --mode browser",
     "test:watch": "vitest watch",
@@ -83,6 +84,7 @@
     "typescript": "^4.9.5 || ^5.4.5",
     "vite-plugin-node-polyfills": "^0.23.0",
     "vitest": "^3.2.4",
+    "zeitzeuge": "^0.6.6",
     "zod-to-json-schema": "^3.22.4"
   },
   "publishConfig": {

libs/langgraph-core/src/errors.ts

@@ -130,7 +130,12 @@ export class EmptyInputError extends BaseLangGraphError {
 
 export class EmptyChannelError extends BaseLangGraphError {
   constructor(message?: string, fields?: BaseLangGraphErrorFields) {
+    // Skip expensive stack trace capture — this error is used for
+    // control flow in hot paths (channel reads) rather than exceptional cases.
+    const prevLimit = Error.stackTraceLimit;
+    Error.stackTraceLimit = 0;
     super(message, fields);
+    Error.stackTraceLimit = prevLimit;
     this.name = "EmptyChannelError";
   }
 

libs/langgraph-core/src/hash.ts

@@ -78,10 +78,10 @@ function assert(a: boolean) {
   if (!a) throw new Error("Assert failed");
 }
 
+const bswap64Scratch = new DataView(new ArrayBuffer(8));
 function bswap64(a: bigint) {
-  const scratchbuf = new DataView(new ArrayBuffer(8));
-  scratchbuf.setBigUint64(0, a, true);
-  return scratchbuf.getBigUint64(0, false);
+  bswap64Scratch.setBigUint64(0, a, true);
+  return bswap64Scratch.getBigUint64(0, false);
 }
 
 function bswap32(input: bigint) {
@@ -476,13 +476,14 @@ function XXH3_len_129to240_128b(
   return h128l | (h128h << n(64));
 }
 
+const encoder = new TextEncoder();
+const hexDigest = (data: bigint) => data.toString(16).padStart(32, "0");
+
 // 16 byte min input
 export function XXH3(input: Uint8Array | string, seed: bigint = n(0)) {
-  const encoder = new TextEncoder();
   const data = view(typeof input === "string" ? encoder.encode(input) : input);
   const len = data.byteLength;
 
-  const hexDigest = (data: bigint) => data.toString(16).padStart(32, "0");
   if (len <= 16) return hexDigest(XXH3_len_0to16_128b(data, seed));
   if (len <= 128) return hexDigest(XXH3_len_17to128_128b(data, kkey, seed));
   if (len <= 240) return hexDigest(XXH3_len_129to240_128b(data, kkey, seed));