Add deno.readAll() (#1234)

js/buffer.ts

@@ -221,3 +221,11 @@ export class Buffer implements Reader, Writer {
     }
   }
 }
+
+/** Read `r` until EOF and return the content as `Uint8Array`.
+ */
+export async function readAll(r: Reader): Promise<Uint8Array> {
+  const buf = new Buffer();
+  await buf.readFrom(r);
+  return buf.bytes();
+}

js/buffer_test.ts

+import { Buffer, readAll } from "deno";
 // This code has been ported almost directly from Go's src/bytes/buffer_test.go
 // Copyright 2009 The Go Authors. All rights reserved. BSD license.
 // https://github.com/golang/go/blob/master/LICENSE
-import { test, assert, assertEqual } from "./test_util.ts";
-import { Buffer } from "deno";
+import { assert, assertEqual, test } from "./test_util.ts";
 
 // N controls how many iterations of certain checks are performed.
 const N = 100;
@@ -193,3 +193,13 @@ test(async function bufferTestGrow() {
     }
   }
 });
+
+test(async function testReadAll() {
+  init();
+  const reader = new Buffer(testBytes.buffer as ArrayBuffer);
+  const actualBytes = await readAll(reader);
+  assertEqual(testBytes.byteLength, actualBytes.byteLength);
+  for (let i = 0; i < testBytes.length; ++i) {
+    assertEqual(testBytes[i], actualBytes[i]);
+  }
+});

js/deno.ts

@@ -20,7 +20,7 @@ export {
   ReadWriteCloser,
   ReadWriteSeeker
 } from "./io";
-export { Buffer } from "./buffer";
+export { Buffer, readAll } from "./buffer";
 export { mkdirSync, mkdir } from "./mkdir";
 export { makeTempDirSync, makeTempDir } from "./make_temp_dir";
 export { chmodSync, chmod } from "./chmod";