Code files

Chapter04/decoupling-io/backpressure/direct-write-with-backpressure.js

@@ -0,0 +1,28 @@
+'use strict'
+
+const { Readable, Writable } = require('readable-stream')
+
+var i = 20
+
+const rs = Readable({
+  read: (size) => {
+    setImmediate(function () {
+      rs.push(i-- ? Buffer.alloc(size) : null)
+    })
+  }
+})
+
+const ws = Writable({
+  write: (chunk, enc, cb) => {
+    console.log(ws._writableState.length)
+    setTimeout(cb, 1)
+  }
+})
+
+rs.on('data', (chunk) => {
+  const writable = ws.write(chunk)
+  if (writable === false) { 
+    rs.pause()
+    ws.once('drain', () => rs.resume())
+  }
+})