How to make request body type compatible with RequestInit or BodyInit when using node-fetch?

user_963879 0
Viewed 32409

I started to use Typescript for my nodejs project. For accessing some external API, I use node-fetch to make requests. While setting up a PUT request, an error pops up, saying that the given body is not assignable to type RequestInit:

The error:

Error:(176, 28) TS2345:Argument of type '{ headers: Headers; method: string; body: MyClass; }' is not assignable to parameter of type 'RequestInit'.
  Types of property 'body' are incompatible.
    Type 'MyClass' is not assignable to type 'BodyInit'.
      Type 'MyClass' is not assignable to type 'ReadableStream'.
        Property 'readable' is missing in type 'MyClass'.

MyClass:

class MyClass {
  configId: string;
  adapterType: string;
  address: string;

  constructor(configId: string, adapterType: string, address: string) {
    this.configId = configId;
    this.adapterType = adapterType;
    this.address = address;
  }

  // some methods
}

Invocation:

let body = new MyClass("a", "b", "c")
let url = config.url + "/dialog/" + dialogId
let headers = new Headers()
// Append several headers

let params = {
  headers: headers,
  method: "PUT",
  body: body
}

return new Promise((resolve, reject) => {
  Fetch(url, params) // <-- error is shown for params variable
    .then(res => {
      // Do stuff
      resolve(/*somevalue*/)
    })
}

How should I make the body object compatible?

node-fetch typescript node.js
3 Answers

You need to stringify your body:

let params: RequestInit = {
  headers: headers,
  method: "PUT",
  body: JSON.stringify(body)
}
user_18949070

I had to import RequestInit from node-fetch rather than using the inbuilt typescript one.

i.e.

This:

import fetch, { RequestInit } from 'node-fetch'

let params: RequestInit = {
  headers: headers,
  method: "PUT",
  body: JSON.stringify(body)
}

NOT this:

import fetch from 'node-fetch'

let params: RequestInit = {
  headers: headers,
  method: "PUT",
  body: JSON.stringify(body)
}
user_44515780
Related