stream: add readableEnded

Author: ronag

doc/api/stream.md

@@ -1095,6 +1095,15 @@ added: REPLACEME
 Getter for the property `encoding` of a given `Readable` stream. The `encoding`
 property can be set using the [`readable.setEncoding()`][] method.
 
+##### readable.readableFinished
+<!-- YAML
+added: REPLACEME
+-->
+
+* {boolean}
+
+Becomes `true` when [`'end'`][] event is emitted.
+
 ##### readable.readableHighWaterMark
 <!-- YAML
 added: v9.3.0

lib/_stream_readable.js

@@ -202,6 +202,16 @@ Object.defineProperty(Readable.prototype, 'destroyed', {
   }
 });
 
+Object.defineProperty(Readable.prototype, 'readableEnded', {
+  // Making it explicit this property is not enumerable
+  // because otherwise some prototype manipulation in
+  // userland will fail
+  enumerable: false,
+  get() {
+    return this._readableState.endEmitted;
+  }
+});
+
 Readable.prototype.destroy = destroyImpl.destroy;
 Readable.prototype._undestroy = destroyImpl.undestroy;
 Readable.prototype._destroy = function(err, cb) {

lib/internal/streams/end-of-stream.js

@@ -42,7 +42,8 @@ function eos(stream, opts, callback) {
     if (!readable) callback.call(stream);
   };
 
-  var readableEnded = stream._readableState && stream._readableState.endEmitted;
+  var readableEnded = stream.readableEnded ||
+    (stream._readableState && stream._readableState.endEmitted);
   const onend = () => {
     readable = false;
     readableEnded = true;

test/parallel/test-stream-readable-ended.js

@@ -0,0 +1,33 @@
+'use strict';
+
+const common = require('../common');
+const { Readable } = require('stream');
+const assert = require('assert');
+
+// basic
+{
+  // Find it on Readable.prototype
+  assert(Readable.prototype.hasOwnProperty('readableEnded'));
+}
+
+// event
+{
+  const readable = new Readable();
+
+  readable._read = () => {
+    // The state finished should start in false.
+    assert.strictEqual(readable.readableEnded, false);
+    readable.push('asd');
+    assert.strictEqual(readable.readableEnded, false);
+    readable.push(null);
+    assert.strictEqual(readable.readableEnded, false);
+  };
+
+  readable.on('end', common.mustCall(() => {
+    assert.strictEqual(readable.readableEnded, true);
+  }));
+
+  readable.on('data', common.mustCall(() => {
+    assert.strictEqual(readable.readableEnded, false);
+  }));
+}