Chapter 3: Samples

Chapter03/transform-stream/transform-stream.js

@@ -0,0 +1,15 @@
+const fs = require("fs");
+const { Transform } = require("stream");
+
+const rs = fs.createReadStream("./file.txt");
+
+const newFile = fs.createWriteStream("./newFile.txt");
+
+const uppercase = new Transform({
+  transform(chunk, encoding, callback) {
+    // Data processing
+    callback(null, chunk.toString().toUpperCase());
+  },
+});
+
+rs.pipe(uppercase).pipe(newFile);