feat: added Xavier's loader file

lesson_10/libraries/src/loaders/loaders.module.ts

@@ -1,10 +1,11 @@
 import { Module } from '@nestjs/common';
 import { AnthonyMaysLoader } from './anthony_mays_loader.js';
+import { XavierCruzLoader } from './xavier_cruz_loader.js';
 
 export const Loaders = Symbol.for('Loaders');
 
 // Add your quiz provider here.
-const LOADER_PROVIDERS = [AnthonyMaysLoader];
+const LOADER_PROVIDERS = [AnthonyMaysLoader, XavierCruzLoader];
 
 @Module({
   providers: [

lesson_10/libraries/src/loaders/xavier_cruz_loader.ts

@@ -0,0 +1,71 @@
+import csv from 'csv-parser';
+import fs from 'fs';
+import { Credit, MediaItem, Role } from '../models/index.js';
+import { Loader } from './loader.js';
+
+export class XavierCruzLoader implements Loader {
+  getLoaderName(): string {
+    return 'xaviercruz';
+  }
+
+  async loadData(): Promise<MediaItem[]> {
+    const credits = await this.loadCredits();
+    const mediaItems = await this.loadMediaItems();
+
+    console.log(
+      `Loaded ${credits.length} credits and ${mediaItems.length} media items`,
+    );
+
+    credits.forEach((credit) => {
+      const mediaItem = mediaItems.find(
+        (media) => media.getId() === credit.getMediaItemId(),
+      );
+
+      if (mediaItem) {
+        mediaItem.addCredit(credit);
+      }
+    });
+
+    return [...mediaItems.values()];
+  }
+
+  async loadMediaItems(): Promise<MediaItem[]> {
+    const mediaItems = [];
+    const readable = fs
+      .createReadStream('data/media_items.csv', 'utf-8')
+      .pipe(csv());
+
+    for await (const row of readable) {
+      const { id, type, title, year } = row;
+      mediaItems.push(new MediaItem(id, title, type, year, []));
+    }
+
+    return mediaItems;
+  }
+
+  async loadCredits(): Promise<Credit[]> {
+    const filePath = 'data/credits.csv';
+    const fileContents = fs.readFileSync(filePath, 'utf-8');
+
+    const lines = fileContents.split('\n');
+    const contentByLine = lines.slice(1);
+
+    for (let i = 0; i < contentByLine.length; i++) {
+      contentByLine[i] = contentByLine[i].substring(
+        contentByLine[i].indexOf(',') + 1,
+      );
+    }
+
+    // help from ChatGPT - Fixing the roleStr as Role issue
+    const credits: Credit[] = contentByLine.map((credit) => {
+      const [mediaItemId, roleStr, name] = credit.split(',');
+
+      // cast roleStr to Role type
+      const role: Role = roleStr as Role;
+
+      return new Credit(mediaItemId, name, role);
+    });
+
+    return credits;
+  }
+}