stream: add helpers to create internal state

Author: MattiasBuelens

lib/internal/webstreams/readablestream.js

@@ -251,19 +251,7 @@ class ReadableStream {
     markTransferMode(this, false, true);
     if (source === null)
       throw new ERR_INVALID_ARG_VALUE('source', 'Object', source);
-    this[kState] = {
-      disturbed: false,
-      reader: undefined,
-      state: 'readable',
-      storedError: undefined,
-      stream: undefined,
-      transfer: {
-        writable: undefined,
-        port1: undefined,
-        port2: undefined,
-        promise: undefined,
-      },
-    };
+    this[kState] = createReadableStreamState();
 
     this[kIsClosedPromise] = createDeferredPromise();
     this[kControllerErrorFunction] = () => {};
@@ -647,19 +635,7 @@ ObjectDefineProperties(ReadableStream, {
 function InternalTransferredReadableStream() {
   markTransferMode(this, false, true);
   this[kType] = 'ReadableStream';
-  this[kState] = {
-    disturbed: false,
-    reader: undefined,
-    state: 'readable',
-    storedError: undefined,
-    stream: undefined,
-    transfer: {
-      writable: undefined,
-      port1: undefined,
-      port2: undefined,
-      promise: undefined,
-    },
-  };
+  this[kState] = createReadableStreamState();
 
   this[kIsClosedPromise] = createDeferredPromise();
 }
@@ -1231,19 +1207,7 @@ ObjectDefineProperties(ReadableByteStreamController.prototype, {
 function InternalReadableStream(start, pull, cancel, highWaterMark, size) {
   markTransferMode(this, false, true);
   this[kType] = 'ReadableStream';
-  this[kState] = {
-    disturbed: false,
-    reader: undefined,
-    state: 'readable',
-    storedError: undefined,
-    stream: undefined,
-    transfer: {
-      writable: undefined,
-      port1: undefined,
-      port2: undefined,
-      promise: undefined,
-    },
-  };
+  this[kState] = createReadableStreamState();
   this[kIsClosedPromise] = createDeferredPromise();
   const controller = new ReadableStreamDefaultController(kSkipThrow);
   setupReadableStreamDefaultController(
@@ -1270,19 +1234,7 @@ function createReadableStream(start, pull, cancel, highWaterMark = 1, size = ()
 function InternalReadableByteStream(start, pull, cancel) {
   markTransferMode(this, false, true);
   this[kType] = 'ReadableStream';
-  this[kState] = {
-    disturbed: false,
-    reader: undefined,
-    state: 'readable',
-    storedError: undefined,
-    stream: undefined,
-    transfer: {
-      writable: undefined,
-      port1: undefined,
-      port2: undefined,
-      promise: undefined,
-    },
-  };
+  this[kState] = createReadableStreamState();
   this[kIsClosedPromise] = createDeferredPromise();
   const controller = new ReadableByteStreamController(kSkipThrow);
   setupReadableByteStreamController(
@@ -1319,6 +1271,22 @@ const isReadableStreamBYOBReader =
 
 // ---- ReadableStream Implementation
 
+function createReadableStreamState() {
+  return {
+    disturbed: false,
+    reader: undefined,
+    state: 'readable',
+    storedError: undefined,
+    stream: undefined,
+    transfer: {
+      writable: undefined,
+      port1: undefined,
+      port2: undefined,
+      promise: undefined,
+    },
+  };
+}
+
 function readableStreamFromIterable(iterable) {
   let stream;
   const iteratorRecord = getIterator(iterable, 'async');

lib/internal/webstreams/writablestream.js

@@ -160,45 +160,7 @@ class WritableStream {
     if (type !== undefined)
       throw new ERR_INVALID_ARG_VALUE.RangeError('type', type);
 
-    this[kState] = {
-      close: createDeferredPromise(),
-      closeRequest: {
-        promise: undefined,
-        resolve: undefined,
-        reject: undefined,
-      },
-      inFlightWriteRequest: {
-        promise: undefined,
-        resolve: undefined,
-        reject: undefined,
-      },
-      inFlightCloseRequest: {
-        promise: undefined,
-        resolve: undefined,
-        reject: undefined,
-      },
-      pendingAbortRequest: {
-        abort: {
-          promise: undefined,
-          resolve: undefined,
-          reject: undefined,
-        },
-        reason: undefined,
-        wasAlreadyErroring: false,
-      },
-      backpressure: false,
-      controller: undefined,
-      state: 'writable',
-      storedError: undefined,
-      writeRequests: [],
-      writer: undefined,
-      transfer: {
-        readable: undefined,
-        port1: undefined,
-        port2: undefined,
-        promise: undefined,
-      },
-    };
+    this[kState] = createWritableStreamState();
 
     this[kIsClosedPromise] = createDeferredPromise();
     this[kControllerErrorFunction] = () => {};
@@ -330,45 +292,7 @@ ObjectDefineProperties(WritableStream.prototype, {
 function InternalTransferredWritableStream() {
   markTransferMode(this, false, true);
   this[kType] = 'WritableStream';
-  this[kState] = {
-    close: createDeferredPromise(),
-    closeRequest: {
-      promise: undefined,
-      resolve: undefined,
-      reject: undefined,
-    },
-    inFlightWriteRequest: {
-      promise: undefined,
-      resolve: undefined,
-      reject: undefined,
-    },
-    inFlightCloseRequest: {
-      promise: undefined,
-      resolve: undefined,
-      reject: undefined,
-    },
-    pendingAbortRequest: {
-      abort: {
-        promise: undefined,
-        resolve: undefined,
-        reject: undefined,
-      },
-      reason: undefined,
-      wasAlreadyErroring: false,
-    },
-    backpressure: false,
-    controller: undefined,
-    state: 'writable',
-    storedError: undefined,
-    writeRequests: [],
-    writer: undefined,
-    transfer: {
-      readable: undefined,
-      port1: undefined,
-      port2: undefined,
-      promise: undefined,
-    },
-  };
+  this[kState] = createWritableStreamState();
 
   this[kIsClosedPromise] = createDeferredPromise();
 }
@@ -584,7 +508,42 @@ ObjectDefineProperties(WritableStreamDefaultController.prototype, {
 function InternalWritableStream(start, write, close, abort, highWaterMark, size) {
   markTransferMode(this, false, true);
   this[kType] = 'WritableStream';
-  this[kState] = {
+  this[kState] = createWritableStreamState();
+  this[kIsClosedPromise] = createDeferredPromise();
+
+  const controller = new WritableStreamDefaultController(kSkipThrow);
+  setupWritableStreamDefaultController(
+    this,
+    controller,
+    start,
+    write,
+    close,
+    abort,
+    highWaterMark,
+    size
+  )
+}
+
+ObjectSetPrototypeOf(InternalWritableStream.prototype, WritableStream.prototype);
+ObjectSetPrototypeOf(InternalWritableStream, WritableStream);
+
+function createWritableStream(start, write, close, abort, highWaterMark = 1, size = () => 1) {
+  const stream = new InternalWritableStream(start, write, close, abort, highWaterMark, size);
+
+  // For spec compliance the InternalWritableStream must be a WritableStream
+  stream.constructor = WritableStream;
+  return stream;
+}
+
+const isWritableStream =
+  isBrandCheck('WritableStream');
+const isWritableStreamDefaultWriter =
+  isBrandCheck('WritableStreamDefaultWriter');
+const isWritableStreamDefaultController =
+  isBrandCheck('WritableStreamDefaultController');
+
+function createWritableStreamState() {
+  return {
     close: createDeferredPromise(),
     closeRequest: {
       promise: undefined,
@@ -623,39 +582,8 @@ function InternalWritableStream(start, write, close, abort, highWaterMark, size)
       promise: undefined,
     },
   };
-  this[kIsClosedPromise] = createDeferredPromise();
-
-  const controller = new WritableStreamDefaultController(kSkipThrow);
-  setupWritableStreamDefaultController(
-    this,
-    controller,
-    start,
-    write,
-    close,
-    abort,
-    highWaterMark,
-    size
-  )
 }
 
-ObjectSetPrototypeOf(InternalWritableStream.prototype, WritableStream.prototype);
-ObjectSetPrototypeOf(InternalWritableStream, WritableStream);
-
-function createWritableStream(start, write, close, abort, highWaterMark, size) {
-  const stream = new InternalWritableStream(start, write, close, abort, highWaterMark, size);
-
-  // For spec compliance the InternalWritableStream must be a WritableStream
-  stream.constructor = WritableStream;
-  return stream;
-}
-
-const isWritableStream =
-  isBrandCheck('WritableStream');
-const isWritableStreamDefaultWriter =
-  isBrandCheck('WritableStreamDefaultWriter');
-const isWritableStreamDefaultController =
-  isBrandCheck('WritableStreamDefaultController');
-
 function isWritableStreamLocked(stream) {
   return stream[kState].writer !== undefined;
 }