Minor refactor

Split utility functions to separate file. Group all the utilities being
used by video type.

src/common.ts

@@ -4,7 +4,7 @@ type ProcessEventCallback = (event: ProcessEvent) => void;
 
 type ErrorEventCallback = (event: Error) => void;
 
-type SuccessEvent = { type: string, output: Buffer };
+type SuccessEvent = { contentType: string, content: Buffer };
 
 type SuccessEventCallback = (event: SuccessEvent) => void;
 
@@ -12,7 +12,7 @@ export interface VideoClipEventEmitter extends NodeJS.EventEmitter {
   process(): void;
   on(eventType: 'process', callback: ProcessEventCallback): this;
   on(eventType: 'error', callback: ErrorEventCallback): this;
-  on(eventType: 'end', callback: ErrorEventCallback): this;
+  on(eventType: 'end', callback: () => void): this;
   on(eventType: 'success', callback: SuccessEventCallback): this;
 }
 

src/video-types/youtube.ts

@@ -1,142 +0,0 @@
-import { EventEmitter } from 'events';
-import { spawnSync } from 'child_process';
-import { readFileSync, unlinkSync } from 'fs';
-import { CreateBaseClipperParams, FILE_TYPES, VideoClipEventEmitter } from '../common';
-import { convertDurationToSeconds, convertSecondsToDuration } from '../duration';
-
-const normalizeStartSeconds = (start?: number | string) => {
-  if (typeof start === 'undefined') {
-    return 0;
-  }
-  if (typeof start === 'string') {
-    return convertDurationToSeconds(start);
-  }
-
-  return start;
-};
-
-const FORMAT_DEFAULT_ARGS = [
-  '--youtube-skip-dash-manifest',
-  '-f', 'bestvideo+bestaudio',
-];
-
-const getFileExtension = (downloaderExecutablePath: string, url: string) => {
-  const result = spawnSync(
-    downloaderExecutablePath,
-    [
-      ...FORMAT_DEFAULT_ARGS,
-      '--print', 'filename',
-      '-o', '%(ext)s',
-      url,
-    ],
-  );
-
-  if (result.error) {
-    throw result.error;
-  }
-
-  return result.stdout.toString('utf-8').trim();
-};
-
-const constructDownloadSectionsRegex = (start?: number | string, end?: number | string) => {
-  const startSeconds = normalizeStartSeconds(start);
-  if (typeof end !== 'undefined') {
-    const endSeconds = (
-      typeof end === 'string'
-        ? convertDurationToSeconds(end)
-        : end
-    );
-
-    return `*${convertSecondsToDuration(startSeconds)}-${convertSecondsToDuration(endSeconds)}`;
-  }
-
-  if (startSeconds > 0) {
-    return `*${convertSecondsToDuration(startSeconds)}-inf`;
-  }
-
-  return null;
-};
-
-const constructDefaultDownloadArgs = (
-  outputFilename: string,
-  url: string,
-  start?: number | string,
-  end?: number | string,
-) => {
-  const defaultDownloadArgs = [
-    ...FORMAT_DEFAULT_ARGS,
-    '-o', outputFilename,
-  ];
-
-  const downloadSectionsRegex = constructDownloadSectionsRegex(start, end);
-  if (typeof downloadSectionsRegex === 'string') {
-    return [
-      ...defaultDownloadArgs,
-      '--force-keyframes-at-cuts',
-      '--download-sections', downloadSectionsRegex,
-      url,
-    ];
-  }
-
-  return [
-    ...defaultDownloadArgs,
-    url,
-  ];
-};
-
-export interface CreateYouTubeClipperParams extends CreateBaseClipperParams {
-  downloaderExecutablePath?: string;
-}
-
-export class YouTubeVideoClipEventEmitter extends EventEmitter implements VideoClipEventEmitter {
-  constructor(private readonly params: CreateYouTubeClipperParams) {
-    super();
-  }
-
-  process() {
-    if (!this.params.downloaderExecutablePath) {
-      this.emit('error', new Error('Downloader not found.'));
-      this.emit('end');
-      return;
-    }
-
-    const fileExtension = getFileExtension(
-      this.params.downloaderExecutablePath,
-      this.params.url,
-    );
-    const cacheFilename = `output.${fileExtension}`; // todo label this on the cache
-    const downloadArgs = constructDefaultDownloadArgs(
-      cacheFilename,
-      this.params.url,
-      this.params.start,
-      this.params.end,
-    );
-
-    this.emit('process', {
-      type: 'download',
-      phase: 'start',
-      command: `${this.params.downloaderExecutablePath} ${downloadArgs.join(' ')}`,
-    });
-    const downloaderProcess = spawnSync(
-      this.params.downloaderExecutablePath,
-      downloadArgs,
-    );
-    if (downloaderProcess.error) {
-      this.emit('error', downloaderProcess.error);
-      this.emit('end');
-      return;
-    }
-    this.emit('process', {
-      type: 'download',
-      phase: 'success',
-    });
-
-    const output = readFileSync(cacheFilename);
-    unlinkSync(cacheFilename);
-    this.emit('success', {
-      type: FILE_TYPES[fileExtension],
-      output,
-    });
-    this.emit('end');
-  }
-}

src/video-types/youtube/index.ts

@@ -0,0 +1,62 @@
+import { EventEmitter } from 'events';
+import { spawnSync } from 'child_process';
+import { readFileSync, unlinkSync } from 'fs';
+import { CreateBaseClipperParams, FILE_TYPES, VideoClipEventEmitter } from '../../common';
+import { getFileExtension, constructDefaultDownloadArgs } from './utilities';
+
+export interface CreateYouTubeClipperParams extends CreateBaseClipperParams {
+  downloaderExecutablePath?: string;
+}
+
+export class YouTubeVideoClipEventEmitter extends EventEmitter implements VideoClipEventEmitter {
+  constructor(private readonly params: CreateYouTubeClipperParams) {
+    super();
+  }
+
+  process() {
+    if (!this.params.downloaderExecutablePath) {
+      this.emit('error', new Error('Downloader not found.'));
+      this.emit('end');
+      return;
+    }
+
+    const fileExtension = getFileExtension(
+      this.params.downloaderExecutablePath,
+      this.params.url,
+    );
+    const cacheFilename = `output.${fileExtension}`; // todo label this on the cache
+    const downloadArgs = constructDefaultDownloadArgs(
+      cacheFilename,
+      this.params.url,
+      this.params.start,
+      this.params.end,
+    );
+
+    this.emit('process', {
+      type: 'download',
+      phase: 'start',
+      command: `${this.params.downloaderExecutablePath} ${downloadArgs.join(' ')}`,
+    });
+    const downloaderProcess = spawnSync(
+      this.params.downloaderExecutablePath,
+      downloadArgs,
+    );
+    if (downloaderProcess.error) {
+      this.emit('error', downloaderProcess.error);
+      this.emit('end');
+      return;
+    }
+    this.emit('process', {
+      type: 'download',
+      phase: 'success',
+    });
+
+    const output = readFileSync(cacheFilename);
+    unlinkSync(cacheFilename);
+    this.emit('success', {
+      contentType: FILE_TYPES[fileExtension],
+      content: output,
+    });
+    this.emit('end');
+  }
+}

src/video-types/youtube/utilities.ts

@@ -0,0 +1,82 @@
+import { spawnSync } from 'child_process';
+import { convertDurationToSeconds, convertSecondsToDuration } from '../../duration';
+
+export const normalizeStartSeconds = (start?: number | string) => {
+  if (typeof start === 'undefined') {
+    return 0;
+  }
+  if (typeof start === 'string') {
+    return convertDurationToSeconds(start);
+  }
+
+  return start;
+};
+
+const FORMAT_DEFAULT_ARGS = [
+  '--youtube-skip-dash-manifest',
+  '-f', 'bestvideo+bestaudio',
+];
+
+export const getFileExtension = (downloaderExecutablePath: string, url: string) => {
+  const result = spawnSync(
+    downloaderExecutablePath,
+    [
+      ...FORMAT_DEFAULT_ARGS,
+      '--print', 'filename',
+      '-o', '%(ext)s',
+      url,
+    ],
+  );
+
+  if (result.error) {
+    throw result.error;
+  }
+
+  return result.stdout.toString('utf-8').trim();
+};
+
+export const constructDownloadSectionsRegex = (start?: number | string, end?: number | string) => {
+  const startSeconds = normalizeStartSeconds(start);
+  if (typeof end !== 'undefined') {
+    const endSeconds = (
+      typeof end === 'string'
+        ? convertDurationToSeconds(end)
+        : end
+    );
+
+    return `*${convertSecondsToDuration(startSeconds)}-${convertSecondsToDuration(endSeconds)}`;
+  }
+
+  if (startSeconds > 0) {
+    return `*${convertSecondsToDuration(startSeconds)}-inf`;
+  }
+
+  return null;
+};
+
+export const constructDefaultDownloadArgs = (
+  outputFilename: string,
+  url: string,
+  start?: number | string,
+  end?: number | string,
+) => {
+  const defaultDownloadArgs = [
+    ...FORMAT_DEFAULT_ARGS,
+    '-o', outputFilename,
+  ];
+
+  const downloadSectionsRegex = constructDownloadSectionsRegex(start, end);
+  if (typeof downloadSectionsRegex === 'string') {
+    return [
+      ...defaultDownloadArgs,
+      '--force-keyframes-at-cuts',
+      '--download-sections', downloadSectionsRegex,
+      url,
+    ];
+  }
+
+  return [
+    ...defaultDownloadArgs,
+    url,
+  ];
+};

test/index.test.ts

@@ -36,19 +36,19 @@ describe('createVideoClipper', () => {
       (spawnSync as Mock).mockReset();
     });
 
-    it('calls the downloader function', () => new Promise((done) => {
+    it('calls the downloader function', () => new Promise<void>((done) => {
       (spawnSync as Mock)
         .mockReturnValueOnce({ stdout: Buffer.from('mkv') })
         .mockReturnValueOnce({ stdout: Buffer.from('') });
 
-      clipper.on('end', done);
+      clipper.on('end', () => { done(); });
       clipper.process();
       expect(spawnSync).toBeCalledTimes(2);
       expect(spawnSync).nthCalledWith(1, 'yt-dlp', expect.arrayContaining(['--print']));
       expect(spawnSync).nthCalledWith(2, 'yt-dlp', expect.anything());
     }));
 
-    it('emits downloader errors', () => new Promise((done) => {
+    it('emits downloader errors', () => new Promise<void>((done) => {
       const causeError = new Error('generic downloader message');
       (spawnSync as Mock)
         .mockReturnValueOnce({ stdout: Buffer.from('mkv') })
@@ -57,27 +57,27 @@ describe('createVideoClipper', () => {
       clipper.on('error', (err: Error) => {
         expect(err).toHaveProperty('message', causeError.message);
       });
-      clipper.on('end', done);
+      clipper.on('end', () => { done(); });
       clipper.process();
     }));
 
-    it('calls the buffer extract function', () => new Promise((done) => {
+    it('calls the buffer extract function', () => new Promise<void>((done) => {
       (spawnSync as Mock)
         .mockReturnValueOnce({ stdout: Buffer.from('mkv') })
         .mockReturnValueOnce({ stdout: Buffer.from('') });
 
-      clipper.on('end', done);
+      clipper.on('end', () => { done(); });
       clipper.process();
 
       expect(readFileSync).toBeCalled();
     }));
 
-    it('calls the cleanup function', () => new Promise((done) => {
+    it('calls the cleanup function', () => new Promise<void>((done) => {
       (spawnSync as Mock)
         .mockReturnValueOnce({ stdout: Buffer.from('mkv') })
         .mockReturnValueOnce({ stdout: Buffer.from('') });
 
-      clipper.on('end', done);
+      clipper.on('end', () => { done(); });
       clipper.process();
 
       expect(unlinkSync).toBeCalled();