Добавит потоки

src/cli/commands/import.command.ts

@@ -1,18 +1,29 @@
 import { TSVFileReader } from '../../shared/libs/file-reader/tsv-file-reader.js';
+import { Offer } from '../../shared/types/offer-type.js';
 import { Command } from './command.interface.js';
 
 export class ImportCommand implements Command {
   public getName(): string {
     return '--import';
   }
 
-  public execute(...parameters: string[]): void {
+  private onImportedOffer(offer: Offer): void {
+    console.info(offer);
+  }
+
+  private onCompleteImport(count: number) {
+    console.info(`${count} rows imported`);
+  }
+
+  public async execute(...parameters: string[]): Promise<void> {
     const [filename] = parameters;
     const fileReader = new TSVFileReader(filename.trim());
 
+    fileReader.on('line', this.onImportedOffer);
+    fileReader.once('end', this.onCompleteImport);
+
     try {
       fileReader.read();
-      console.log(fileReader.toArray());
     } catch (err) {
       if (!(err instanceof Error)) {
         throw err;

src/shared/libs/file-reader/tsv-file-reader.ts

@@ -1,18 +1,15 @@
-import { readFileSync } from 'node:fs';
+import EventEmitter from 'node:events';
+import { createReadStream } from 'node:fs';
+
 import { FileReader } from './index.js';
 import { Offer, TypeUser } from '../../types/index.js';
-export class TSVFileReader implements FileReader {
-  private rawData = '';
+export class TSVFileReader extends EventEmitter implements FileReader {
+  private CHUNK_SIZE = 16384;
 
   constructor(
     private readonly filename: string
-  ) {}
-
-  private parseRawDataToOffers(): Offer[] {
-    return this.rawData
-      .split('\n')
-      .filter((row) => row.trim().length > 0)
-      .map((line) => this.parseLineToOffer(line));
+  ) {
+    super();
   }
 
   private parseLineToOffer(line: string): Offer {
@@ -80,18 +77,30 @@ export class TSVFileReader implements FileReader {
     return {name, email, avatarUser, password, typeUser:TypeUser[typeUser as 'Pro' | 'Usual']};
   }
 
-  private validateRawData(): void {
-    if (! this.rawData) {
-      throw new Error('File was not read');
-    }
-  }
+  public async read(): Promise<void> {
+    const readStream = createReadStream(this.filename, {
+      highWaterMark: this.CHUNK_SIZE,
+      encoding: 'utf-8'
+    });
 
-  public read(): void {
-    this.rawData = readFileSync(this.filename, 'utf-8');
-  }
+    let remainingData = '';
+    let nextLinePosititon = -1;
+    let importedRowCouint = 0;
 
-  public toArray(): Offer[] {
-    this.validateRawData();
-    return this.parseRawDataToOffers();
+    for await (const chunk of readStream) {
+      remainingData += chunk.toString();
+
+      while((nextLinePosititon = remainingData.indexOf('\n')) >= 0) {
+        const completeRow = remainingData.slice(0, nextLinePosititon + 1);
+        remainingData = remainingData.slice(++nextLinePosititon);
+        importedRowCouint++;
+
+        const parsedOffer = this.parseLineToOffer(completeRow);
+        this.emit('line', parsedOffer);
+      }
+    }
+
+    this.emit('end', importedRowCouint);
   }
 }
+

src/shared/libs/file-writer/file-writer.interface.ts

@@ -0,0 +1,3 @@
+export interface FileWriter {
+  write(row: string): void;
+}

src/shared/libs/file-writer/index.ts

@@ -0,0 +1 @@
+export { FileWriter } from './file-writer.interface.js';

src/shared/libs/file-writer/tsv-file-wtiter.ts

@@ -0,0 +1,28 @@
+import { FileWriter } from './index.js';
+import { WriteStream } from 'node:fs';
+import { createWriteStream } from 'node:fs';
+
+export class TSVFileWriter implements FileWriter {
+
+  private stream: WriteStream;
+
+  constructor(filename: string) {
+    this.stream = createWriteStream(filename, {
+      flags: 'w',
+      encoding: 'utf-8',
+      autoClose: true
+    });
+  }
+
+  public async write(row: string): Promise<unknown> {
+    const writeSuccess = this.stream.write(`${row}\n`);
+
+    if (! writeSuccess) {
+      return new Promise((resolve) => {
+        this.stream.once('drain', () => resolve(true));
+      });
+    }
+
+    return Promise.resolve();
+  }
+}