Why writes that types are incompatible?

Question

Angular

There is an interface

export interface Applications {
  "date": string,
  "firm": string,
  "full name": string,
  "phone": string,
  "comment": string,
  "code": string
}

I am trying to pass a variable with this data type to a post request

this.body = new HttpParams({
      fromObject: this.variable
})

But for some reason it writes to me that

Type 'Applications' is not assignable to type '{ [param: string]: string | number | boolean | readonly (string | number | boolean)[]; }'.

The interface completely matches the type in the error, what's wrong?

Answer 1

You continue to read that message:

Type 'Applications' is not assignable to type '{ [param: string]: string | number | boolean | readonly (string | number | boolean)[]; }'.
Index signature for type 'string' is missing in type 'Applications'

This is how it will work:

export type Applications = {
  "date": string,
  "firm": string,
  "full name": string,
  "phone": string,
  "comment": string,
  "code": string
}

What the hell is this your Index signature google yourself.