Added liking and security measures

features/relations/friend_graph.js

@@ -0,0 +1,39 @@
+const driver = require("../../graph_db");
+
+function graphIdToNumber(value) {
+  if (typeof value === "number") return value;
+  if (value && typeof value.toNumber === "function") return value.toNumber();
+  return Number(value);
+}
+
+function graphParams(userId) {
+  return { db_id: Number(userId) };
+}
+
+async function getFriendIds(userId) {
+  const { records } = await driver.executeQuery(
+    "MATCH (me:Person {db_id: $db_id})-[:FRIENDS_WITH]-(f:Person) RETURN f.db_id AS id",
+    graphParams(userId),
+    { database: process.env.GRAPH_DB_NAME },
+  );
+  return new Set(records.map((record) => graphIdToNumber(record.get("id"))));
+}
+
+async function getFriendIdsAmong(userId, ids) {
+  if (ids.length === 0) return new Set();
+  const { records } = await driver.executeQuery(
+    `MATCH (me:Person {db_id: $db_id})-[:FRIENDS_WITH]-(f:Person)
+     WHERE f.db_id IN $ids
+     RETURN f.db_id AS id`,
+    { ...graphParams(userId), ids: ids.map(Number) },
+    { database: process.env.GRAPH_DB_NAME },
+  );
+  return new Set(records.map((record) => graphIdToNumber(record.get("id"))));
+}
+
+async function areFriends(userId, otherId) {
+  const friendIds = await getFriendIdsAmong(userId, [otherId]);
+  return friendIds.has(Number(otherId));
+}
+
+module.exports = { getFriendIds, getFriendIdsAmong, areFriends, graphIdToNumber };