title: HttpHeaders Link

Purpose

An Apollo Link to easily transform headers from being a key-value object to an instance of HttpHeaders (@angular/common/http). Great combination with apollo-angular-link-http.

Installation

npm install apollo-angular-link-headers@beta --save

Usage

The httpHeaders function takes no arguments. Its only task is to take headers property (key-value object) of a operation context and transform it into an instance of HttpHeaders class (from @angular/common/http) to make it work with apollo-angular-link-http.

import { httpHeaders } from 'apollo-angular-link-headers';
import { HttpLink } from 'apollo-angular-link-http';

const headers = httpHeaders();
const http = http.create();

const link = headers.concat(http);

It creates a bridge between other Apollo Links that uses headers as a plain object, so you can do things like:

import { setContext } from 'apollo-link-context';

const middleware = setContext((request, previousContext) => ({
  authorization: 'token'
}));