Merge pull request #311 from ali-ince/1.5-add-passing-bookmark-example

Add example for passing bookmarks

Author: ali-ince

src/v1/internal/bookmark.js

@@ -90,10 +90,13 @@ function asStringArray(value) {
     const result = [];
     for (let i = 0; i < value.length; i++) {
       const element = value[i];
-      if (!util.isString(element)) {
-        throw new TypeError(`Bookmark should be a string, given: '${element}'`);
+      // if it is undefined or null, ignore it
+      if (element !== undefined && element !== null) {
+        if (!util.isString(element)) {
+          throw new TypeError(`Bookmark should be a string, given: '${element}'`);
+        }
+        result.push(element);
       }
-      result.push(element);
     }
     return result;
   }

test/v1/examples.test.js

@@ -508,6 +508,99 @@ describe('examples', () => {
       done();
     });
   });
+
+  it('pass bookmarks example', done => {
+    const driver = driverGlobal;
+
+    // tag::pass-bookmarks[]
+    // Create a company node
+    function addCompany(tx, name) {
+      return tx.run('CREATE (a:Company {name: $name})', {'name': name});
+    }
+
+    // Create a person node
+    function addPerson(tx, name) {
+      return tx.run('CREATE (a:Person {name: $name})', {'name': name});
+    }
+
+    // Create an employment relationship to a pre-existing company node.
+    // This relies on the person first having been created.
+    function addEmployee(tx, personName, companyName) {
+      return tx.run('MATCH (person:Person {name: $personName}) ' +
+        'MATCH (company:Company {name: $companyName}) ' +
+        'CREATE (person)-[:WORKS_FOR]->(company)', {'personName': personName, 'companyName': companyName});
+    }
+
+    // Create a friendship between two people.
+    function makeFriends(tx, name1, name2) {
+      return tx.run('MATCH (a:Person {name: $name1}) ' +
+        'MATCH (b:Person {name: $name2}) ' +
+        'MERGE (a)-[:KNOWS]->(b)', {'name1': name1, 'name2': name2});
+    }
+
+    // To collect friend relationships
+    const friends = [];
+
+    // Match and display all friendships.
+    function findFriendships(tx) {
+      const result = tx.run('MATCH (a)-[:KNOWS]->(b) RETURN a.name, b.name');
+
+      result.subscribe({
+        onNext: record => {
+          const name1 = record.get(0);
+          const name2 = record.get(1);
+
+          friends.push({'name1': name1, 'name2': name2});
+        }
+      });
+    }
+
+    // To collect the session bookmarks
+    const savedBookmarks = [];
+
+    // Create the first person and employment relationship.
+    const session1 = driver.session(neo4j.WRITE);
+    const first = session1.writeTransaction(tx => addCompany(tx, 'Wayne Enterprises')).then(
+      () => session1.writeTransaction(tx => addPerson(tx, 'Alice'))).then(
+      () => session1.writeTransaction(tx => addEmployee(tx, 'Alice', 'Wayne Enterprises'))).then(
+      () => {
+        savedBookmarks.push(session1.lastBookmark());
+
+        return session1.close();
+      });
+
+    // Create the second person and employment relationship.
+    const session2 = driver.session(neo4j.WRITE);
+    const second = session2.writeTransaction(tx => addCompany(tx, 'LexCorp')).then(
+      () => session2.writeTransaction(tx => addPerson(tx, 'Bob'))).then(
+      () => session2.writeTransaction(tx => addEmployee(tx, 'Bob', 'LexCorp'))).then(
+      () => {
+        savedBookmarks.push(session2.lastBookmark());
+
+        return session2.close();
+      });
+
+    // Create a friendship between the two people created above.
+    const last = Promise.all([first, second]).then(ignore => {
+      const session3 = driver.session(neo4j.WRITE, savedBookmarks);
+
+      return session3.writeTransaction(tx => makeFriends(tx, 'Alice', 'Bob')).then(
+        () => session3.readTransaction(findFriendships).then(
+          () => session3.close()
+        )
+      );
+    });
+    // end::pass-bookmarks[]
+
+    last.then(() => {
+      expect(friends.length).toBe(1);
+      expect(friends[0].name1).toBe('Alice');
+      expect(friends[0].name2).toBe('Bob');
+
+      done();
+    });
+  });
+
 });
 
 function removeLineBreaks(string) {