Add opusscript as a possible opus encoder (#558)

* Add opusscript as a possible opus encoder

* Make weird eslint rule happy

src/client/voice/opus/OpusScriptEngine.js

@@ -0,0 +1,28 @@
+const OpusEngine = require('./BaseOpusEngine');
+
+let Opusscript;
+
+class NodeOpusEngine extends OpusEngine {
+  constructor(player) {
+    super(player);
+    try {
+      // eslint-disable-next-line import/no-unresolved
+      Opusscript = require('opusscript');
+    } catch (err) {
+      throw err;
+    }
+    this.encoder = new Opusscript(48000, 2);
+  }
+
+  encode(buffer) {
+    super.encode(buffer);
+    return this.encoder.encode(buffer, 960);
+  }
+
+  decode(buffer) {
+    super.decode(buffer);
+    return this.encoder.decode(buffer);
+  }
+}
+
+module.exports = NodeOpusEngine;