Merge pull request #13024 from meteor/339-observe-async-3x

339 Support observeChangesAsync and observeAsync and keep ASYNC the rest [Meteor 3.x]

packages/minimongo/cursor.js

@@ -216,6 +216,16 @@ export default class Cursor {
     return LocalCollection._observeFromObserveChanges(this, options);
   }
 
+  /**
+   * @summary observe async version
+   * @locus Anywhere
+   * @memberOf Promise<Mongo.Cursor>
+   * @instance
+   */
+  observeAsync(options) {
+    return new Promise(resolve => resolve(this.observe(options)));
+  }
+
   /**
    * @summary Watch a query. Receive callbacks as the result set changes. Only
    *          the differences between the old and new documents are passed to
@@ -373,6 +383,19 @@ export default class Cursor {
     return handle;
   }
 
+  /**
+   * @summary observeChanges async version
+   * @locus Anywhere
+   * @memberOf Promise<Mongo.Cursor>
+   * @instance
+   */
+  observeChangesAsync(options) {
+    return new Promise((resolve) => {
+      const handle = this.observeChanges(options);
+      handle.isReadyPromise.then(() => resolve(handle));
+    });
+  }
+
   // XXX Maybe we need a version of observe that just calls a callback if
   // anything changed.
   _depend(changers, _allow_unordered) {

packages/mongo/mongo_driver.js

@@ -940,6 +940,10 @@ Cursor.prototype.observe = function (callbacks) {
   return LocalCollection._observeFromObserveChanges(self, callbacks);
 };
 
+Cursor.prototype.observeAsync = function (callbacks) {
+  return new Promise(resolve => resolve(this.observe(callbacks)));
+};
+
 Cursor.prototype.observeChanges = function (callbacks, options = {}) {
   var self = this;
   var methods = [
@@ -965,6 +969,10 @@ Cursor.prototype.observeChanges = function (callbacks, options = {}) {
     self._cursorDescription, ordered, callbacks, options.nonMutatingCallbacks);
 };
 
+Cursor.prototype.observeChangesAsync = async function (callbacks, options = {}) {
+  return this.observeChanges(callbacks, options);
+};
+
 MongoConnection.prototype._createSynchronousCursor = function(
     cursorDescription, options) {
   var self = this;

packages/mongo/mongo_livedata_tests.js

@@ -4302,3 +4302,40 @@ Tinytest.addAsync('mongo-livedata - maintained isomorphism using resolverType co
 
   test.equal(items, []);
 });
+
+testAsyncMulti("mongo-livedata - support observeChangesAsync and observeAsync to keep isomorphism on client and server", [
+  async (test) => {
+    const Collection = new Mongo.Collection(`observe_changes_async${test.runId()}`, { resolverType: 'stub' });
+    const id = 'a';
+    await Collection.insertAsync({ _id: id, foo: { bar: 123 } });
+
+    return new Promise(async resolve => {
+      const obs = await Collection.find(id).observeChangesAsync({
+        async changed(_id, fields) {
+          await obs.stop();
+          resolve();
+          test.equal(_id, id);
+          test.equal(fields?.foo?.bar, 456);
+        },
+      });
+      await Collection.updateAsync(id, { $set: { 'foo.bar': 456 } });
+    });
+  },
+  async (test) => {
+    const Collection = new Mongo.Collection(`observe_async${test.runId()}`, { resolverType: 'stub' });
+    const id = 'a';
+    await Collection.insertAsync({ _id: id, foo: { bar: 123 } });
+
+    return new Promise(async resolve => {
+      const obs = await Collection.find(id).observeAsync({
+        async changed(newDocument) {
+          await obs.stop();
+          test.equal(newDocument._id, id);
+          test.equal(newDocument?.foo?.bar, 456);
+          resolve();
+        },
+      });
+      await Collection.updateAsync(id, { $set: { 'foo.bar': 456 } });
+    });
+  }
+]);