Challenge: Building APIs

Practice implementing a working version of the Credit-Check API.


In this challenge, you finally get to code the API. That means you’ll be using the design assets along with Node.js and the DARRT library to implement a working version of the Credit-Check API.

  1. First, copy the DARRT library into your Node.js project.
  2. Next, use information from the ALPS document and WSD diagram to update the DARRT library files.
  3. Finally, fire up the completed Credit-Check API and run the validator script to ensure the service at least supports the intended happy-path workflow.

Implement your API

You’ll need to use design documents from the project’s assets folder as guides while you implement the API. You can rely on the resource diagram (credit-check-http.png) and ALPS profile (credit-check-alps.xml or credit-check-alps.json) to help you fill in the data.js, actions.js, resources.js, and transitions.js files.

For this challenge, you won’t need to update the representations.js file because it’s already been set up for all the output formats needed for this project. You’ll also notice that the data.js file has been set up with the common basic data properties id, status, and dateCreated, dateUpdated. You’ll only need to add the fields defined by the credit-check design. The actions.js, resources.js, and transitions.js files will need to be updated to match your design specifications.

Validate your API’s workflow

Finally, after updating the DARRT files, your API should be ready for validation. For this challenge, you can run the script provided in the API folder. To run this, execute the sh tests/ command. Then, match your output with the output provided in the cat tests/hp-credit-check-output.txt text file in the same folder.


As usual, practice the tasks given above in the terminal below. The DARRT library has been already copied to the API folder.

Note: Don’t forget to execute npm run dev in the second terminal. Make sure you set the path by executing cd usercode/credit-check before doing so. You can click the “+” sign to open the second terminal.

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