Coding challenge to demonstrate API development skills with NodeJS
Our users have points in their accounts. Users only see a single balance in their accounts. But for reporting purposes we actually track their points per payer/partner. In our system, each transaction record contains: payer (string), points (integer), timestamp (date).
For earning points it is easy to assign a payer, we know which actions earned the points. And thus which partner should be paying for the points.
When a user spends points, they don't know or care which payer the points come from. But, our accounting team does care how the points are spent. There are two rules for determining what points to "spend" first:
- We want the oldest points to be spent first (oldest based on transaction timestamp, not the order they’re received)
- We want no payer's points to go negative.
- NodeJs https://nodejs.org/en/ , use the LTS version!
- Postman https://www.postman.com/, use this to make requests to the API
- Download the project either by cloning the project or downloading the ZIP file and extracting the project in its own directory
- Navigate to the project directory
- Run the command
npm install - Run the command
npm run start - The Points API server will start on port 3000 by default, take note of which port it responds with and make your requests to that port as needed.
GET http://localhost:3000/point
Example response:
{
"DANNON": 1100,
"UNILEVER": 200,
"MILLER COORS": 10000
}
POST http://localhost:3000/point
BODY content-type = application/x-www-form-urlencoded
Key | Example Value | Validation Rules
payer | TEST | string, required
points | 2000 | integer, required
timestamp | 2020-10-02T14:01:00Z | timestamp (Iso-8601 formatted works), required
Example response:
[
{
"payer": "DANNON",
"points": 1000,
"timestamp": "2020-11-02T14:00:00Z"
},
{
"payer": "UNILEVER",
"points": 200,
"timestamp": "2020-10-31T11:00:00Z"
},
{
"payer": "TEST",
"points": 2000,
"timestamp": "2020-10-02T14:01:00Z"
}
]
POST http://localhost:3000/point/spend
BODY content-type = application/x-www-form-urlencoded
Key | Example Value | Validation Rules
points | 5000 | integer, required
Example response:
{
"ALDI": -4000,
"DANNON": -700,
"UNILEVER": 0,
"MILLER COORS": -300
}
NOTE: If your total point balance is insufficient for spending the amount specified, you will get an error saying so and you will not be able to spend the point amount.
{
"message": "Balance is insufficient."
}