JavaScript: User Transactions
Date
Author
Implement a function getNumTransactions(). It takes a username and it returns either the number of transactions associated with username, or a string “Username Not Found” if no such user exists. Make a GET request to the given REST APIs that contain information about a user.
Given a user name, the user details should be fetched by making a GET call to the API https://jsonmock.hackerrank.com/api/article_users?username=<username> where <username> is the parameter passed to the getNumTransactions function.
The response will be a JSON object with the following 5 fields:
page: The current page of the results. (Number)
per_page: The maximum number of results returned per page. (Number)
total: The total number of results. (Number)
total_pages: The total number of pages with results. (Number)
data: Either an empty array or an array with a single object containing the user details record with the following schema:
id – user id (Number)
username – user name as passed above (String)
This object has other fields as well but they are not needed for this question.
If the username passed to the request does not exist in the system, the data array will be empty. In that case, the function should return “Username Not Found”.
An example of a user record is as follows:
{
"id": 1,
"username": "epaga"
}If the user details is successfully fetched from the first API, use the id property of the details object to fetch the transactions information for the user. The API to fetch this is https://jsonmock.hackerrank.com/api/transactions?&userId=<userId> where <userId> is the id property fetched earlier.
The response will be a JSON object with the following 5 fields:
page: The current page of the results. (Number)
per_page: The maximum number of results returned per page. (Number)
total: The total number of transactions for the given user id. (Number)
total_pages: The total number of pages with results. (Number)
data: Either an empty array or an array with transaction records of the user.
Here total is the total number of transactions of the user and is the final value to be returned by the function.
Here is an example of a response:
{
page: 1,
per_page: 10,
total: 75,
total_pages: 8,
data: [
// Data contains the list of user transactions matching the user ID.
{
"id": 8,
"userId": 1,
"userName": "Francesco De Mello",
"timestamp": 1548805761859,
"txnType": "credit",
"amount": "$1,214.44",
...
}
]
}As per this example final value to be returned is 75.
Input Format For Custom Testing
In the first and only line, there is a user name.
Sample Case 0
Sample Input For Custom Testing
epaga
Sample Output
79
Explanation
First a call is made to API https://jsonmock.hackerrank.com/api/article_users?username=epaga to fetch the user id which is 1 per the response. Then a second call is made to API https://jsonmock.hackerrank.com/api/transactions?userId=1 to fetch the total number of transactions which is 79 per the response.
Sample Case 1
Sample Input For Custom Testing
jay
Sample Output
Username Not Found
Explanation
An API call is made to https://jsonmock.hackerrank.com/api/article_users?username=jay to get the user id but the data field in the response is an empty array. Hence ‘Username Not Found’ is returned by the function.
SOLUTION:
'use strict';
const fs = require('fs');
const https = require('https');
process.stdin.resume();
process.stdin.setEncoding('utf-8');
let inputString = '';
let currentLine = 0;
process.stdin.on('data', function(inputStdin) {
inputString += inputStdin;
});
process.stdin.on('end', function() {
inputString = inputString.split('\n');
main();
});
function readLine() {
return inputString[currentLine++];
}
const axios = require('axios');
async function getNumTransactions(username) {
let url = `https://jsonmock.hackerrank.com/api/article_users?username=${username}`;
let response = await axios.get(url);
if (response.data.data.length === 0) {
return 'Username Not Found';
}
let userId = response.data.data[0].id;
url = `https://jsonmock.hackerrank.com/api/transactions?&userId=${userId}`;
response = await axios.get(url);
return response.data.total;
}
async function main() {
const ws = fs.createWriteStream(process.env.OUTPUT_PATH);
const username = readLine().trim();
const result = await getNumTransactions(username);
ws.write(result.toString());
}