概要

jsonwebtokenlibが Node v24で動作せず、
buffer-equal-constant-time ライブラリがエラーを投げてしまう.

var origSlowBufEqual = SlowBuffer.prototype.equal;
                                  ^

TypeError: Cannot read properties of undefined (reading 'prototype')
    at Object.<anonymous> (/Users/user/testnode24/node_modules/buffer-equal-constant-time/index.js:37:35)
    at Module._compile (node:internal/modules/cjs/loader:1734:14)
    at Object..js (node:internal/modules/cjs/loader:1899:10)
    at Module.load (node:internal/modules/cjs/loader:1469:32)
    at Module._load (node:internal/modules/cjs/loader:1286:12)
    at TracingChannel.traceSync (node:diagnostics_channel:322:14)
    at wrapModuleLoad (node:internal/modules/cjs/loader:235:24)
    at Module.require (node:internal/modules/cjs/loader:1491:12)
    at require (node:internal/modules/helpers:135:16)
    at Object.<anonymous> (/Users/user/testnode24/node_modules/jwa/index.js:1:19)

Node.js v24.0.0

また、Auth.js (NextAuth.js)内 auth.tsなどにおいて
クライアントサイドでjsonwebtokenを使用しようとすることによりエラーが投げられてしまう.

 GET /api/auth/session 500 in 470ms
 
 ⨯ TypeError: Cannot read properties of undefined (reading 'prototype')
    at __webpack_require__ (.next/server/webpack-runtime.js:33:43)
    at __webpack_require__ (.next/server/webpack-runtime.js:33:43)
    at __webpack_require__ (.next/server/webpack-runtime.js:33:43)
    at __webpack_require__ (.next/server/webpack-runtime.js:33:43)
    at __webpack_require__ (.next/server/webpack-runtime.js:33:43)
    at __webpack_require__ (.next/server/webpack-runtime.js:33:43)
    at eval (webpack-internal:///(rsc)/./src/auth.ts:14:70)
    at __webpack_require__.a (.next/server/webpack-runtime.js:105:13)
    at eval (webpack-internal:///(rsc)/./src/auth.ts:1:21)
    at <unknown> (rsc)/./src/auth.ts (/Users/user/project/client/.next/server/app/api/auth/[...nextauth]/route.js:54:1)
    at __webpack_require__ (.next/server/webpack-runtime.js:33:43)
    at eval (webpack-internal:///(rsc)/./src/app/api/auth/[...nextauth]/route.ts:7:63)
    at __webpack_require__.a (.next/server/webpack-runtime.js:105:13)
    at eval (webpack-internal:///(rsc)/./src/app/api/auth/[...nextauth]/route.ts:1:21)
    at <unknown> (rsc)/./src/app/api/auth/[...nextauth]/route.ts (/Users/user/project/client/.next/server/app/api/auth/[...nextauth]/route.js:43:1)
    at __webpack_require__ (.next/server/webpack-runtime.js:33:43)
    at __webpack_require__.a (.next/server/webpack-runtime.js:105:13)
    at __webpack_require__ (.next/server/webpack-runtime.js:33:43)
    at __webpack_exec__ (.next/server/app/api/auth/[...nextauth]/route.js:206:39)
    at <unknown> (.next/server/app/api/auth/[...nextauth]/route.js:207:714)
    at __webpack_require__.X (.next/server/webpack-runtime.js:237:21)
    at <unknown> (.next/server/app/api/auth/[...nextauth]/route.js:207:47)
    at Object.<anonymous> (.next/server/app/api/auth/[...nextauth]/route.js:210:3) {
  page: '/api/auth/session'
}

原因

jsonwebtoken が依存している jws が依存している jwa lib内で
SlowBuffer.prototype.equalを用いてバッファ比較が行われますが、
NodeJS v24.0.0のリリースでこのAPIが削除されたため動作できなかったことが原因です.

修正方法

jwaにおいてパッチ版がリリースされたため、以下にバージョンを合わせた上で
npm i（またはプロジェクトの依存再構築cmd）を実行することで解決できます。

package.json

"dependencies": {
    "jsonwebtoken": "^9.0.2",
    "jws": "^3.2.2",
    "jwa": "^1.4.2"
}

参照

auth0 / node-jsonwebtoken Issue
https://github.com/auth0/node-jsonwebtoken/issues/992