feat: adds CSV loader for LJ (#435)

* feat: solved merge conflict and generated loader file

* fix: Capitalized and punctuated my comments properly

* fix: fixed one capitalization I missed previously

* Update loaders.module.ts

---------

Co-authored-by: Anthony D. Mays <[email protected]>

Author: marleomac3

lesson_10/libraries/src/loaders/lj_mcwilliams_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 LjMcwilliamsLoader implements Loader {
+  getLoaderName(): string {
+    return 'ljmcwilliams';
+  }
+
+  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`,
+    );
+
+    return [...mediaItems.values()];
+  }
+
+  async loadMediaItems(): Promise<MediaItem[]> {
+    // TODO: Implement this method.
+    const media = [];
+    const readable = fs
+      .createReadStream('data/media_items.csv', 'utf-8')
+      .pipe(csv());
+    for await (const row of readable) {
+      /**This destructures the CSV file rows. */
+      const { id, type, title, year } = row;
+      media.push(new MediaItem(id, title, type, year, []));
+    }
+    return media;
+  }
+
+  /*
+  An asyncchronous function named loadCredits
+  returns a Promise of an array of Credit Objects.
+  */
+  async loadCredits(): Promise<Credit[]> {
+    //The empty credits array will store parsed credit data
+    const credits = [];
+    /**
+     * This var creates a readable stream from the CSV file and
+     * is piped through the csv function to parse the data.
+     */
+    const readable = fs
+      .createReadStream('data/credits.csv', 'utf-8')
+      .pipe(csv());
+    //This asynchronously iterates over each row of the parsed CSV data.
+    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

@@ -10,6 +10,7 @@ import { HummadTanweerLoader } from './hummad_tanweer_loader.js';
 import { JamesCapparellLoader } from './james_capparell_loader.js';
 import { JosephCaballeroLoader } from './joseph_caballero_loader.js';
 import { KimberleeHaldaneLoader } from './kimberlee_haldane_loader.js';
+import { LjMcwilliamsLoader } from './lj_mcwilliams_loader.js';
 import { NileJacksonLoader } from './nile_jackson_loader.js';
 import { OyeyemiJimohLoader } from './oyeyemi_jimoh_loader.js';
 import { PabloLimonParedesLoader } from './pablo_limon_paredes_loader.js';
@@ -32,6 +33,7 @@ const LOADER_PROVIDERS = [
   JamesCapparellLoader,
   JosephCaballeroLoader,
   KimberleeHaldaneLoader,
+  LjMcwilliamsLoader,
   NileJacksonLoader,
   OyeyemiJimohLoader,
   PabloLimonParedesLoader,