44d1a1cb15
This PR is part of a larger effort to migrate error messages to MDX and use App Router: https://github.com/vercel/front/pull/23459
27 lines
909 B
Text
27 lines
909 B
Text
---
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title: It looks like the next instance is being instantiated incorrectly.
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---
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## Why This Error Occurred
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You have passed a null or undefined parameter to the `next()` call.
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## Possible Ways to Fix It
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Make sure you are passing the variables properly:
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```js filename="server.js"
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const app = next()
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```
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And make sure you're passing dev as shown in the examples below:
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```js filename="server.js"
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const app = next({ dev: boolean })
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```
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## Useful Links
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- [custom-server-express](https://github.com/vercel/next.js/blob/6ca00bfe312c8d3fc5c20d25a9cd8d2741a29332/examples/custom-server-express/server.js#L6)
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- [custom-server](https://github.com/vercel/next.js/blob/6ca00bfe312c8d3fc5c20d25a9cd8d2741a29332/examples/custom-server/server.js#L6)
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- [custom-server-typescript](https://github.com/vercel/next.js/blob/6ca00bfe312c8d3fc5c20d25a9cd8d2741a29332/examples/custom-server-typescript/server/index.ts#L7)
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