now only scrapes events that are not already scraped

src/scrape.js

@@ -140,7 +140,6 @@ const open_browser = async (images_directory) => {
   return browser;
 };
 
-const { page_ids } = parse_args(process.argv.slice(2));
 const register_upcoming_events_listener = (endpoint, page) => {
   let responses = [];
   return new Promise((resolve, reject) => {
@@ -163,9 +162,25 @@ const register_upcoming_events_listener = (endpoint, page) => {
   });
 };
 
+const { page_ids, output, events: event_file } = parse_args(
+  process.argv.slice(2),
+);
+
+const read_previous_events = (path) => {
+  if (path !== null) {
+    return fs
+      .readFile(path, { encoding: 'utf-8' })
+      .then((content) => JSON.parse(content))
+      .catch(console.error);
+  }
+  return Promise.resolve([]);
+};
+
 (async () => {
   create_images_directory('./events/img');
 
+  const previous_events = await read_previous_events(event_file);
+
   const browser = await open_browser();
 
   let events = [];
@@ -202,6 +217,12 @@ const register_upcoming_events_listener = (endpoint, page) => {
     const new_events = nodes.map(map_event);
 
     events = merge_edges(new_events, events);
+    events = events.filter(
+      ({ event_id }) =>
+        previous_events.find(
+          (previous_event) => event_id === previous_event.event_id,
+        ) === undefined,
+    );
 
     events = await Promise.all(
       events.map(async (event) => {
@@ -226,5 +247,9 @@ const register_upcoming_events_listener = (endpoint, page) => {
     }),
   );
 
-  console.log(JSON.stringify(events));
+  if (output === null) {
+    console.log(JSON.stringify([...events, ...previous_events]));
+  }
+
+  process.exit();
 })();