Add multiple-output example

Author: jeromewu

examples/node/multiple-output.js

@@ -0,0 +1,15 @@
+const fs = require('fs');
+const { createFFmpeg } = require('../../src');
+
+const ffmpeg = createFFmpeg({ log: true });
+
+(async () => {
+  await ffmpeg.load();
+  await ffmpeg.write('flame.avi', '../../tests/assets/flame.avi');
+  await ffmpeg.run('-i flame.avi -map 0:v -r 25 out_%06d.bmp');
+  ffmpeg.ls('/').filter((p) => p.endsWith('.bmp')).forEach((p) => {
+    fs.writeFileSync(p, ffmpeg.read(p));
+  });
+
+  process.exit(0);
+})();