data.js

const csv = require("csv-parser");
const fs = require("fs");
const results = [];
const resultsWithRank = [];
const track1 = "# of Skill Badges Completed in Track 1",
	track2 = "# of Skill Badges Completed in Track 2";
fs.createReadStream("data/data.csv")
	.pipe(csv())
	.on("data", (data) => results.push(data))
	.on("end", () => {
		let id = 0;
		let institute = results[0]["Institution"];
		results.forEach((result) => {
			delete result["Enrolment Date & Time"];
			delete result["Qwiklabs Profile URL"];
			delete result["Institution"];
			delete result["Student Email"];
			result.id = id++;
		});
		results.sort(
			(a, b) =>
				Number(b[track1]) +
					Number(b[track2]) -
					(Number(a[track1]) + Number(a[track2])) ||
				a["Student Name"] - b["Student Name"]
		);
		let rank = 1;

		//set first entry rank = 1 since the array is already sorted
		results[0]["Rank"] = rank;

		//iterate over entries, check if the number of quests completed are same as the previous entry.
		//If they are same then give them the same rank else increment the rank
		for (let pointer = 1; pointer < results.length; pointer++) {
			let totalNumberOfQuestsCompletedByPreviousRank =
				Number(results[pointer - 1][track1]) +
				Number(results[pointer - 1][track2]);
			let totalNumberOfQuestsCompleted =
				Number(results[pointer][track1]) + Number(results[pointer][track2]);

			//if total # of quests completed is 0 then we increment the rank
			if (totalNumberOfQuestsCompleted === 0) {
				rank++;
				results[pointer]["Rank"] = rank;
			}
			//if total # of quests completed is equal to the previous entry then we give them the same rank
			else if (
				totalNumberOfQuestsCompletedByPreviousRank ===
				totalNumberOfQuestsCompleted
			) {
				results[pointer]["Rank"] = results[pointer - 1]["Rank"];
			} else {
				rank++;
				results[pointer]["Rank"] = rank;
			}
		}

		//we want the rank column to be on the left of the name, hence create a new array of objects where the first key would be 'Rank'
		results.forEach((result) => {
			let obj = {
				Rank: result["Rank"],
				"Student Name": result["Student Name"],
				"Enrolment Status": result["Enrolment Status"],
				"# of Skill Badges Completed in Track 1": result[track1],
				"# of Skill Badges Completed in Track 2": result[track2],
				id: result["id"],
			};

			resultsWithRank.push(obj);
		});

		fs.writeFile(
			"data/data.json",
			JSON.stringify({
				resultsWithRank,
				buildDate: new Date(Date.now()).toDateString(),
				institute,
			}),
			(err) => {
				if (err) throw err;
				console.log("Data file has been saved!");
			}
		);
	});