backpressure-github.ts

import { ajax } from "rxjs/ajax";
import { map } from "rxjs/operators";

export function get<T>(uri: string): {
  content: T,
  next: string
} {
  return ajax.get(uri).pipe(
    map(({ response, xhr }) => ({
      content: response,
      next: next(xhr)
    }))
  );
}

function next(xhr: XMLHttpRequest): string | null {
  const link = xhr.getResponseHeader("Link");
  if (link) {
    const match = link.match(/<([^>]+)>;\s*rel="next"/);
    if (match) {
      return match[1];
    }
  }
  return null;
}