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Graph/e8e59edd-cf26-4c00-82ec-e73afd970640

Problemunvalidated

Next.js middleware throws "Cannot read properties of undefined (reading 'custom')" when connecting to MongoDB

e8e59edd-cf26-4c00-82ec-e73afd970640

Next.js middleware throws "Cannot read properties of undefined (reading 'custom')" when connecting to MongoDB

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Updated4/30/2026

PageRank0.0000

Effectiveness0.000

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22 linked nodes

DESCRIBESQuestion

DESCRIBESQuestion

MANIFESTS_ASSymptom

Cannot read properties of undefined (reading 'custom')

ESCALATES_TOProblem

after implementing middleware I get this error every time I make a call — after implementing middleware. Tension: The project works without any issues. But after implementing middleware I get this error every time I make a call. Outcome: MAY I KNOW WHAT THE REAL ISSUE IS. HOW TO FIX THAT.

CAUSED_BYRootCause

Mongoose does not currently support Next.js Edge Runtime

CAUSED_BYRootCause

await connectToMongoDB(); — instrumentation.ts. Outcome: if (process.env.NEXT_RUNTIME !== 'nodejs') return;.

PERTAIN_TODomain

PERTAIN_TODomain

FIXED_BYSolution

Define/initialize the custom `storage` first (move `const storage` above `useBearStore`) and then pass it to `createJSONStorage(() => storage)` for the persist middleware.

FIXED_BYSolution

Update the mongodb version and avoid using Mongoose in Next.js Edge Runtime; move the database access to a Node.js runtime

FIXED_BYSolution

if I use a custom middleware class without inheriting from `BaseHTTPMiddleware` — context variables get propagated correctly to the uvicorn access logger. Tension: known starlette `BaseHTTPMiddleware` limitation of not propagating contextvars "upwards". Outcome: the solution would be along the lines of:.

FIXED_BYSolution

if (process.env.NEXT_RUNTIME !== 'nodejs') return; — instrumentation.ts. Outcome: await connectToMongoDB();.

FIXED_BYSolution

it works just fine — from one of the pages. Tension: when I am calling it from the `middleware.js` that clerk is using I am getting this error.

OCCURS_ONComponent

OCCURS_ONPackage

OCCURS_ONLanguage

INSTANCE_OFClusterConcept

Router State Mismatch

Shared Model Snapshot Gap

Deprecated Config Property Migration

Uninitialized Persistent Storage

Routing Metadata in Middleware

Contextvars Lost Across Middleware

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