Add function to download and update data

package.json

@@ -13,6 +13,8 @@
   },
   "devDependencies": {
     "@tsconfig/node18": "^18.2.2",
+    "@types/adm-zip": "^0.5.3",
+    "@types/d3": "^7.4.2",
     "aws-cdk-lib": "2.101.1",
     "constructs": "10.2.69",
     "prettier": "^3.0.3",
@@ -21,5 +23,10 @@
   },
   "workspaces": [
     "packages/*"
-  ]
+  ],
+  "dependencies": {
+    "adm-zip": "^0.5.10",
+    "d3": "^7.8.5",
+    "node-fetch": "^3.3.2"
+  }
 }

packages/functions/src/config/index.ts

@@ -0,0 +1,8 @@
+export const BASE_URL: string = `https://singapore-ev-trends.ruchern.xyz`;
+
+export enum FUEL_TYPE {
+  DIESEL = "Diesel",
+  ELECTRIC = "Electric",
+  OTHERS = "Others",
+  PETROL = "Petrol",
+}

packages/functions/src/lambda.ts

@@ -1,8 +1,81 @@
 import { ApiHandler } from "sst/node/api";
+import fs from "fs";
+import fetch from "node-fetch";
+import * as d3 from "d3";
+import AdmZip from "adm-zip";
+import { FUEL_TYPE } from "./config";
+import { sortByMake } from "./lib/sortByMake";
+import type { Car } from "./types";
 
 export const handler = ApiHandler(async (_evt) => {
-  return {
-    statusCode: 200,
-    body: `Hello world. The time is ${new Date().toISOString()}`,
-  };
+  const tempDir: string = "/tmp";
+  const zipFileName: string = `Monthly New Registration of Cars by Make.zip`;
+  const zipFilePath: string = `${tempDir}/${zipFileName}`;
+  const csvFileName: string = `M03-Car_Regn_by_make.csv`;
+  const csvFilePath: string = `${tempDir}/${csvFileName}`;
+  const zipUrl: string = `https://datamall.lta.gov.sg/content/dam/datamall/datasets/Facts_Figures/Vehicle Registration/${zipFileName}`;
+
+  try {
+    const response = await fetch(zipUrl)
+      .then((response) => {
+        if (!response.ok) {
+          throw new Error(
+            `Failed to download the ZIP file: ${response.statusText}`,
+          );
+        }
+        return response.buffer();
+      })
+      .then((data) => {
+        fs.writeFileSync(zipFilePath, data);
+      })
+      .catch((error) =>
+        console.error("Error while downloading the ZIP file:", error),
+      );
+
+    const zip = new AdmZip(zipFilePath);
+    zip.extractAllTo(`${tempDir}`, true);
+
+    const csvData = fs.readFileSync(csvFilePath, "utf-8");
+
+    const parsedData = d3.csvParse(csvData);
+
+    const electricCars: Car[] = parsedData
+      .filter(
+        ({ fuel_type, number }) =>
+          fuel_type === FUEL_TYPE.ELECTRIC && +number !== 0,
+      )
+      .reduce((result: Car[], { month, make, fuel_type, number }) => {
+        const existingCar = result.find(
+          (car) => car.month === month && car.make === make,
+        );
+
+        if (existingCar) {
+          existingCar.number += Number(number);
+        } else {
+          result.push({
+            month,
+            make,
+            fuel_type,
+            number: Number(number),
+          });
+        }
+
+        return result;
+      }, [])
+      .map((car) => ({ ...car, number: +car.number }))
+      .sort(sortByMake);
+
+    console.table(electricCars);
+
+    return {
+      statusCode: 200,
+      body: JSON.stringify(electricCars),
+    };
+  } catch (error) {
+    console.error(error);
+    return {
+      statusCode: 500,
+      body: "Error occurred while processing the ZIP file.",
+    };
+  }
 });

packages/functions/src/lib/sortByMake.ts

@@ -0,0 +1,4 @@
+import type { Car } from "../types";
+
+export const sortByMake = (a: Pick<Car, "make">, b: Pick<Car, "make">) =>
+  a.make.localeCompare(b.make);

packages/functions/src/types/index.ts

@@ -0,0 +1,19 @@
+import { FUEL_TYPE } from "../config";
+
+export interface Car {
+  month: string;
+  make: string;
+  fuel_type: FUEL_TYPE | string;
+  number: number;
+  selected?: boolean;
+}
+
+export type Dataset = {
+  label: string;
+  data: number[];
+};
+
+export interface ChartDataset extends Dataset {
+  borderColor: string;
+  checked: boolean;
+}