Standardize on parse-link-header

li.parse and parseLinkHeader accomplish the same goal.
Using only one of these libraries simplifies dependencies

Author: kadamwhite

lib/autodiscovery.js

@@ -16,13 +16,12 @@ const parseLinkHeader = require( 'parse-link-header' );
  * @returns {String} The URL of the located API root
  */
 function locateAPIRootHeader( response ) {
-	// Define the expected link rel value per http://v2.wp-api.org/guide/discovery/
-	const rel = 'https://api.w.org/';
-
 	// Extract & parse the response link headers
 	const link = response.link || ( response.headers && response.headers.link );
 	const headers = parseLinkHeader( link );
-	const apiHeader = headers && headers[ rel ];
+
+	// See https://developer.wordpress.org/rest-api/using-the-rest-api/discovery/
+	const apiHeader = headers && headers[ 'https://api.w.org/' ];
 
 	if ( apiHeader && apiHeader.url ) {
 		return apiHeader.url;

lib/http-transport.js

@@ -4,7 +4,7 @@
 'use strict';
 
 const agent = require( 'superagent' );
-const parseLinkHeader = require( 'li' ).parse;
+const parseLinkHeader = require( 'parse-link-header' );
 
 const WPRequest = require( './constructors/wp-request' );
 const checkMethodSupport = require( './util/check-method-support' );
@@ -133,7 +133,9 @@ function createPaginationObject( result, options, httpTransport ) {
 	}
 
 	// Decode the link header object
-	const links = result.headers.link ? parseLinkHeader( result.headers.link ) : {};
+	const links = result.headers.link ?
+		parseLinkHeader( result.headers.link ) :
+		{};
 
 	// Store pagination data from response headers on the response collection
 	_paging = {
@@ -147,7 +149,7 @@ function createPaginationObject( result, options, httpTransport ) {
 		_paging.next = new WPRequest( {
 			...options,
 			transport: httpTransport,
-			endpoint: links.next,
+			endpoint: links.next.url,
 		} );
 	}
 
@@ -156,7 +158,7 @@ function createPaginationObject( result, options, httpTransport ) {
 		_paging.prev = new WPRequest( {
 			...options,
 			transport: httpTransport,
-			endpoint: links.prev,
+			endpoint: links.prev.url,
 		} );
 	}