add recorder file

src/background/recorder.ts

@@ -0,0 +1,79 @@
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const portAudio = require('naudiodon');
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const { Writable } = require('stream');
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const { StringDecoder } = require('string_decoder');
+
+interface RecorderI {
+  start(): void;
+  stop(): string;
+}
+
+class StringWritable extends Writable {
+
+  constructor(options: {
+    defaultEncoding: string;
+  }) {
+    super(options);
+    this._decoder = new StringDecoder(options && options.defaultEncoding);
+    this.data = '';
+  }
+
+   _write(chunk: Buffer, encoding: string, callback: (error? : Error) => void) {
+     if (encoding === 'buffer') {
+       chunk = this._decoder.write(chunk);
+     }
+     this.data += chunk;
+     callback();
+   }
+
+   _final(callback: (error? : Error) => void) {
+     this.data += this._decoder.end();
+     callback();
+   }
+
+}
+
+export class Recorder implements RecorderI {
+  
+  private ia: any;
+  private micWritable: StringWritable;
+
+  constructor(options: {
+
+  }) { 
+    this.ia = new portAudio.AudioIO({ 
+      inOptions: options
+    });   
+    this.micWritable = new StringWritable({
+      defaultEncoding: 'binary'
+    });
+    this.start();
+  }
+
+  start(): void {
+    console.log('inititate recording');
+    this.ia.pipe(this.micWritable);
+    this.ia.start();
+    this.ia.pause();
+  }
+
+  record(): void {
+    this.ia.resume();
+  }
+
+  pause(): void {
+     this.ia.pause();
+  }
+
+  getData(): string {
+    return this.micWritable.data;
+  }
+
+  stop(): string {
+    this.ia.quit();
+    return this.micWritable.data;
+  }
+
+}