feat: adds Chanel's media items loader and extra credit (#396)

* feat: adds chanel_hutt_loader.ts

* feat: completed loader.ts file

* feat: completes loader and extra credit for lesson10

Author: NelltheWiz

lesson_10/libraries/src/loaders/chanel_hutt_loader.ts

@@ -0,0 +1,57 @@
+import csv from 'csv-parser';
+import fs from 'fs';
+import { Credit, MediaItem } from '../models/index.js';
+import { Loader } from './loader.js';
+
+export class ChanelHuttLoader implements Loader {
+  getLoaderName(): string {
+    return 'chanelhutt';
+  }
+
+  async loadData(): Promise<MediaItem[]> {
+    const credits = await this.loadCredits();
+    const mediaItems = await this.loadMediaItems();
+    // Create a Hashmap to where the key is a string(MediaItem ID) and the value is the MediaItem object.
+    const hashMapIndex = new Map<string, MediaItem>();
+    // Loops through the mediaItems and adds them to the map by their ID.
+    for (const mediaItem of mediaItems) {
+      hashMapIndex.set(mediaItem.getId(), mediaItem);
+    }
+    // Loops through the credits and adds them to the mediaItem by getting the mediaItem ID.
+    for (const credit of credits) {
+      const mediaItem = hashMapIndex.get(credit.getMediaItemId());
+      if (mediaItem) {
+        mediaItem.addCredit(credit);
+      }
+      console.log(
+        `Loaded ${credits.length} credits and ${mediaItems.length} media items`,
+      );
+    }
+    // Returns an array of the values from the hashmap.
+    return Array.from(hashMapIndex.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, title, type, year } = row;
+      mediaItems.push(new MediaItem(id, title, type, year, []));
+    }
+    return mediaItems;
+  }
+
+  async loadCredits(): Promise<Credit[]> {
+    const credits = [];
+    const readable = fs
+      .createReadStream('data/credits.csv', 'utf-8')
+      .pipe(csv());
+    for await (const row of readable) {
+      const { media_item_id, role, name } = row;
+      credits.push(new Credit(media_item_id, name, role));
+    }
+    return credits;
+  }
+}

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

@@ -1,15 +1,16 @@
 import { Module } from '@nestjs/common';
 
 import { AnthonyMaysLoader } from './anthony_mays_loader.js';
+import { ChanelHuttLoader } from './chanel_hutt_loader.js';
 import { DylanLaffertysLoader } from './dylan_lafferty_loaders.js';
 import { MercedesMathewsLoader } from './mercedes_mathews_loader.js';
 import { MontezBLoader } from './montez_b_loaders.js';
-
 export const Loaders = Symbol.for('Loaders');
 
 const LOADER_PROVIDERS = [
   AnthonyMaysLoader,
   DylanLaffertysLoader,
+  ChanelHuttLoader,
   MercedesMathewsLoader,
   MontezBLoader
 ];