Getting node API up and running - node.js

Question

I am attempting to follow this tutorial on using using node, Express, and postgresql to build and API. All my code for this can be found on Github.
In my server/routes/index.js is the following (the numbering being line numbers).
1: app.get('/api/todos', todosController.list);
2: // app.post('/api/todos/:todoId/items', todoItemsController.create);
3: app.post('/api/todos', todosController.create);
4: app.get('/api/todos/:todoId', todosController.retrieve);
5: app.put('/api/todos/:todoId', todosController.update);
6: app.delete('/api/todos/:todoId', todosController.destroy);
I am having two problems.
The first problem is lines 4 and 5 don't work (all of the other lines do minus line 2). When I use postman/browser to test them I get this error
ReferenceError: TodoItem is not defined
at retrieve (/Users/X-lem/Development/TestAPI/server/controllers/todos.js:25:20)
at Layer.handle [as handle_request] (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/layer.js:95:5)
at next (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/route.js:137:13)
at Route.dispatch (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/route.js:112:3)
at Layer.handle [as handle_request] (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/layer.js:95:5)
at /Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:281:22
at param (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:354:14)
at param (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:365:14)
at Function.process_params (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:410:3)
at next (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:275:10)
at urlencodedParser (/Users/X-lem/Development/TestAPI/node_modules/body-parser/lib/types/urlencoded.js:91:7)
at Layer.handle [as handle_request] (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/layer.js:95:5)
at trim_prefix (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:317:13)
at /Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:284:7
at Function.process_params (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:335:12)
at next (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:275:10)
at jsonParser (/Users/X-lem/Development/TestAPI/node_modules/body-parser/lib/types/json.js:109:7)
at Layer.handle [as handle_request] (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/layer.js:95:5)
at trim_prefix (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:317:13)
at /Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:284:7
at Function.process_params (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:335:12)
at next (/Users/X-lem/Development/TestAPI/node_modules/express/lib/router/index.js:275:10)
Secondly, when I uncomment line 2 the console crashes and I get this error.
ReferenceError: todoItemsController is not defined
at module.exports (/Users/X-lem/Development/TestAPI/server/routes/index.js:9:40)
at Object.<anonymous> (/Users/X-lem/Development/TestAPI/app.js:16:27)
at Module._compile (module.js:612:30)
at Object.Module._extensions..js (module.js:623:10)
at Module.load (module.js:531:32)
at tryModuleLoad (module.js:494:12)
at Function.Module._load (module.js:486:3)
at Module.require (module.js:556:17)
at require (internal/module.js:11:18)
at Object.<anonymous> (/Users/X-lem/Development/TestAPI/bin/www:3:13)
at Module._compile (module.js:612:30)
at Object.Module._extensions..js (module.js:623:10)
at Module.load (module.js:531:32)
at tryModuleLoad (module.js:494:12)
at Function.Module._load (module.js:486:3)
at Function.Module.runMain (module.js:653:10)
at startup (bootstrap_node.js:187:16)
at bootstrap_node.js:608:3
[nodemon] app crashed - waiting for file changes before starting...
I am new to building API's and am trying to teach myself how to do it. I have tried a number of different troubleshooting methods with no avail. Any help is appreciated, thank you.

Answer 1

Hope I can help a little bit. Your problem #2 was because you did mistype. Please, take a look at your routes/index.js file. You imported controllers to the variable todosController, but on the 9-th line you are using not defined variable todoItemsController. So, just
app.post('/api/todos/:todoId/items', todosController.create); will work.