1 files changed, 89 insertions, 0 deletions
diff --git a/cli/js/web/streams/readable_stream_default_reader.ts b/cli/js/web/streams/readable_stream_default_reader.ts
new file mode 100644
index 000000000..9bdce3e9c
--- /dev/null
+++ b/cli/js/web/streams/readable_stream_default_reader.ts
@@ -0,0 +1,89 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+import {
+  Deferred,
+  isReadableStream,
+  isReadableStreamDefaultReader,
+  isReadableStreamLocked,
+  readableStreamDefaultReaderRead,
+  readableStreamReaderGenericCancel,
+  readableStreamReaderGenericInitialize,
+  readableStreamReaderGenericRelease,
+} from "./internals.ts";
+import { ReadableStreamImpl } from "./readable_stream.ts";
+import * as sym from "./symbols.ts";
+import { symbols } from "../../symbols.ts";
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export class ReadableStreamDefaultReaderImpl<R = any>
+  implements ReadableStreamDefaultReader<R> {
+  [sym.closedPromise]: Deferred<void>;
+  [sym.forAuthorCode]: boolean;
+  [sym.ownerReadableStream]: ReadableStreamImpl<R>;
+  [sym.readRequests]: Array<Deferred<ReadableStreamReadResult<R>>>;
+
+  constructor(stream: ReadableStream<R>) {
+    if (!isReadableStream(stream)) {
+      throw new TypeError("stream is not a ReadableStream.");
+    }
+    if (isReadableStreamLocked(stream)) {
+      throw new TypeError("stream is locked.");
+    }
+    readableStreamReaderGenericInitialize(this, stream);
+    this[sym.readRequests] = [];
+  }
+
+  get closed(): Promise<void> {
+    if (!isReadableStreamDefaultReader(this)) {
+      return Promise.reject(
+        new TypeError("Invalid ReadableStreamDefaultReader.")
+      );
+    }
+    return (
+      this[sym.closedPromise].promise ??
+      Promise.reject(new TypeError("Invalid reader."))
+    );
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  cancel(reason?: any): Promise<void> {
+    if (!isReadableStreamDefaultReader(this)) {
+      return Promise.reject(
+        new TypeError("Invalid ReadableStreamDefaultReader.")
+      );
+    }
+    if (!this[sym.ownerReadableStream]) {
+      return Promise.reject(new TypeError("Invalid reader."));
+    }
+    return readableStreamReaderGenericCancel(this, reason);
+  }
+
+  read(): Promise<ReadableStreamReadResult<R>> {
+    if (!isReadableStreamDefaultReader(this)) {
+      return Promise.reject(
+        new TypeError("Invalid ReadableStreamDefaultReader.")
+      );
+    }
+    if (!this[sym.ownerReadableStream]) {
+      return Promise.reject(new TypeError("Invalid reader."));
+    }
+    return readableStreamDefaultReaderRead(this);
+  }
+
+  releaseLock(): void {
+    if (!isReadableStreamDefaultReader(this)) {
+      throw new TypeError("Invalid ReadableStreamDefaultReader.");
+    }
+    if (this[sym.ownerReadableStream] === undefined) {
+      return;
+    }
+    if (this[sym.readRequests].length) {
+      throw new TypeError("Cannot release lock with pending read requests.");
+    }
+    readableStreamReaderGenericRelease(this);
+  }
+
+  [symbols.customInspect](): string {
+    return `ReadableStreamDefaultReader { closed: Promise }`;
+  }
+}