This "solution" given here has a syntax error since you don't have access to `user` within the second then() callback:

    get("http://data.com/user") 
      .then(user => get("http://data.com/location" + user.id))
      .then(location => createEntry(user, location)) 
      .then(response => {
        // handle response 
      }).catch(err => {
        // handle failure
      });

Instead, back before async/await made things easier this nested pattern was used (notice the difference in parenthesis location):

    get("http://data.com/user") 
      .then(user => get("http://data.com/location" + user.id)
        .then(location => createEntry(user, location)))
      .then(response => {
        // handle response 
      }).catch(err => {
        // handle failure
      });

Edit for completeness, this is how it is now with async/await:

    try {
      const user = await get("http://data.com/user"); 
      const location = await get("http://data.com/location" + user.id);
      const response = await createEntry(user, location);
      // handle response 
    } catch (error) {
      // handle failure
    }