feat(presence): Support for arbitrary data

Author: Calyhre

lib/json1.ts

@@ -735,11 +735,11 @@ function transformPresence(presence: Presence | null, op: JSONOp, isOwnOperation
     const end = transformPosition(presence.end, op)
 
     if (start && end) {
-        return { start, end }
+        return { ...presence, start, end }
     } else if (start) {
-        return { start, end: start }
+        return { ...presence, start, end: start }
     } else if (end) {
-        return { start: end, end }
+        return { ...presence, start: end, end }
     }
 
     return null

test/presence.js

@@ -83,4 +83,13 @@ describe("presences", () => {
       presenceAfter
     );
   });
+
+  it("allows arbitrary data in presences", () => {
+    const op = ["z", 0, { i: "hello" }];
+    const data = { user: "John Doe", color: "blue" };
+    const presenceBefore = { start: ["z", 0], end: ["z", 1], data };
+    const presenceAfter = type.transformPresence(presenceBefore, op);
+
+    assert.ok(presenceBefore.data === presenceAfter.data);
+  });
 });