The absence of a 'body' argument in the send() \ json() method within the Next.js API, coupled with TypeScript, raises an important argument

Question

The absence of a 'body' argument in the send() \ json() method within the Next.js API, coupled with TypeScript, raises an important argument

Currently, I have set up an API route within Next.js. Within the 'api' directory, my 'file.tsx' consists of the following code:

import type { NextApiRequest, NextApiResponse } from "next";
const someFunction = (req: NextApiRequest, res: NextApiResponse<data>) => { the rest of the code... }

Everything seems to be functioning properly. However, in relation to the line below:

res.status(200).send();

I am encountering a TypeScript error highlighting send():

Expected 1 arguments, but got 0.ts(2554) utils.d.ts(182, 25): An argument for 'body' was not provided.

Referring to the documentation (https://nextjs.org/docs/api-routes/response-helpers), I attempted adding an argument such as

res.status(200).send({key: "value"})

, or

res.status(200).send("string")

, along with using json() instead of send().

Despite replicating the examples exactly from the documentation, the error persists. Changing the typing temporarily resolved the issue, however, it is likely present for a specific purpose thereby making it an undesirable solution.

Is there something that I may be overlooking here?

typescript next.js typeerror send

Answer 1

Answer №1

Within this context, there are a few things to consider. The initial error being flagged by Typescript is the absence of an argument for 'body'. This issue is relatively clear-cut and easy to address. A secondary error stems from the predefined response type:

res: NextApiResponse<Data>

This structure indicates that the Data type is already specified as:

type Data = {
  name: string;
};

Essentially, it denotes an object containing a property named 'name' with a type of string.

If your intention is to transmit a simple string, you will need to amend the type accordingly to:

type Data = string;

An alternative approach involves directly defining it within the response, such as:


const someFunction = (req: NextApiRequest, res: NextApiResponse<string>) => {
  return res.status(200).json("hello");
};

export default someFunction

In essence, it's crucial to bear in mind that Typescript mandates explicit declaration of the data type sent as a response. The primary purpose of integrating Typescript into a project is to preempt errors by incorporating type safety validations into the codebase.

For additional insights, refer to Everyday Types.

Answer 2

Within this context, there are a few things to consider. The initial error being flagged by Typescript is the absence of an argument for 'body'. This issue is relatively clear-cut and easy to address. A secondary error stems from the predefined response type:

res: NextApiResponse<Data>

This structure indicates that the Data type is already specified as:

type Data = {
  name: string;
};

Essentially, it denotes an object containing a property named 'name' with a type of string.

If your intention is to transmit a simple string, you will need to amend the type accordingly to:

type Data = string;

An alternative approach involves directly defining it within the response, such as:


const someFunction = (req: NextApiRequest, res: NextApiResponse<string>) => {
  return res.status(200).json("hello");
};

export default someFunction

In essence, it's crucial to bear in mind that Typescript mandates explicit declaration of the data type sent as a response. The primary purpose of integrating Typescript into a project is to preempt errors by incorporating type safety validations into the codebase.

For additional insights, refer to Everyday Types.

The absence of a 'body' argument in the send() \ json() method within the Next.js API, coupled with TypeScript, raises an important argument

Answer №1

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