Add Navigator.onLine

https://html.spec.whatwg.org/multipage/system-state.html#dom-navigator-online-dev

Author: toastal

src/Web/HTML/Navigator.js

@@ -12,6 +12,12 @@ exports.languages = function (navigator) {
   };
 };
 
+exports.onLine = function (navigator) {
+  return function () {
+    return navigator.onLine;
+  };
+};
+
 exports.platform = function (navigator) {
   return function () {
     return navigator.platform;

src/Web/HTML/Navigator.purs

@@ -8,6 +8,8 @@ foreign import language :: Navigator -> Effect String
 
 foreign import languages :: Navigator -> Effect (Array String)
 
+foreign import onLine :: Navigator -> Effect Boolean
+
 foreign import platform :: Navigator -> Effect String
 
 foreign import userAgent :: Navigator -> Effect String