getHttpHeadersOrInit.ts

import { Headers } from '@angular/http';
import { getHttpOptionsAndIdx } from './getHttpOptionsAndIdx';

/**
 * @description
 * Gets {@link Headers} from data array.
 * If no {@link RequestOptions} found - creates it and updates original data array.
 * If no {@link Headers} found - creates it and sets to {@link RequestOptions}.
 * @param data - Array of http data
 * @param method - Http method
 */
export function getHttpHeadersOrInit(data: any[], method: string): Headers {
  const { options, idx } = getHttpOptionsAndIdx(data, method);
  let headers = options.headers;

  // Create and update Headers
  if (!options.headers) {
    headers = new Headers();
    options.headers = headers;
  }

  // Set Options back
  data[idx] = options;

  return headers;
}