stabilize Deno.iter() and Deno.iterSync() (#4890)

1 files changed, 13 insertions, 5 deletions

diff --git a/cli/js/io.ts b/cli/js/io.ts
index 023718100..d41914d34 100644
--- a/cli/js/io.ts
+++ b/cli/js/io.ts
@@ -6,6 +6,8 @@
 export const EOF: unique symbol = Symbol("EOF");
 export type EOF = typeof EOF;
 
+const DEFAULT_BUFFER_SIZE = 32 * 1024;
+
 // Seek whence values.
 // https://golang.org/pkg/io/#pkg-constants
 export enum SeekMode {
@@ -71,7 +73,7 @@ export interface ReadWriteSeeker extends Reader, Writer, Seeker {}
 // https://golang.org/pkg/io/#Copy
 export async function copy(dst: Writer, src: Reader): Promise<number> {
   let n = 0;
-  const b = new Uint8Array(32 * 1024);
+  const b = new Uint8Array(DEFAULT_BUFFER_SIZE);
   let gotEOF = false;
   while (gotEOF === false) {
     const result = await src.read(b);
@@ -86,9 +88,12 @@ export async function copy(dst: Writer, src: Reader): Promise<number> {
 
 export async function* iter(
   r: Reader,
-  bufSize?: number
+  options?: {
+    bufSize?: number;
+  }
 ): AsyncIterableIterator<Uint8Array> {
-  const b = new Uint8Array(bufSize ?? 1024);
+  const bufSize = options?.bufSize ?? DEFAULT_BUFFER_SIZE;
+  const b = new Uint8Array(bufSize);
   while (true) {
     const result = await r.read(b);
     if (result === EOF) {
@@ -101,9 +106,12 @@ export async function* iter(
 
 export function* iterSync(
   r: SyncReader,
-  bufSize?: number
+  options?: {
+    bufSize?: number;
+  }
 ): IterableIterator<Uint8Array> {
-  const b = new Uint8Array(bufSize ?? 1024);
+  const bufSize = options?.bufSize ?? DEFAULT_BUFFER_SIZE;
+  const b = new Uint8Array(bufSize);
   while (true) {
     const result = r.readSync(b);
     if (result === EOF) {