Quickest and simplest way to convert fetch JavaScript to work in TypeScript project

What’s the simplest way to get this piece of code working in TypeScript project?

var requestOptions = {
  method: 'GET',
  body: raw,
  redirect: 'follow',
  headers: {
    'x-mock-response-code': '204',
  },
}

fetch(
  'https://abcd.mock.pstmn.io/token',
  requestOptions
)
  .then(response => response.text())
  .then(result => console.log(result))
  .catch(error => console.log('error', error))

I get this error that won’t let me compile:

Argument of type '{ method: string; body: string; redirect: string; headers: { 'x-mock-response-code': string; }; }' is not assignable to parameter of type 'RequestInit'.
   Types of property 'redirect' are incompatible.
     Type 'string' is not assignable to type 'RequestRedirect | undefined'.ts(234

>Solution :

Since you assigned a plain object to requestOptions without specifying a type, TypeScript has inferred what type it should be.

That type thinks redirect is a string, but fetch expects it to be one of a specific selection of strings.

When you later pass the object to fetch, TypeScript thinks the value you used can be any string and you get an error.

You have a couple of options here:

• Be explicit about the types

  That way when you pass the object to fetch it will be of the RequestInit type instead of the inferred type you are currently passing.

    var requestOptions: RequestInit = {
  

• Don’t use the intermediate variable

  If you assign the object directly to the argument, then TypeScript can compare it directly instead of creating a type and then comparing that type.

    fetch(
        'https://abcd.mock.pstmn.io/token',
        {
            // options here
        }
    )