BREAKING CHANGE: change order of args in Deno.copy() (#4885)

3 files changed, 6 insertions, 7 deletions

diff --git a/cli/js/io.ts b/cli/js/io.ts
index d41914d34..50ea1216a 100644
--- a/cli/js/io.ts
+++ b/cli/js/io.ts
@@ -70,8 +70,7 @@ export interface ReadWriteCloser extends Reader, Writer, Closer {}
 // https://golang.org/pkg/io/#ReadWriteSeeker
 export interface ReadWriteSeeker extends Reader, Writer, Seeker {}
 
-// https://golang.org/pkg/io/#Copy
-export async function copy(dst: Writer, src: Reader): Promise<number> {
+export async function copy(src: Reader, dst: Writer): Promise<number> {
   let n = 0;
   const b = new Uint8Array(DEFAULT_BUFFER_SIZE);
   let gotEOF = false;
diff --git a/cli/js/lib.deno.ns.d.ts b/cli/js/lib.deno.ns.d.ts
index c40e42b8c..7145751c7 100644
--- a/cli/js/lib.deno.ns.d.ts
+++ b/cli/js/lib.deno.ns.d.ts
@@ -565,16 +565,16 @@ declare namespace Deno {
    *
    *       const source = await Deno.open("my_file.txt");
    *       const buffer = new Deno.Buffer()
-   *       const bytesCopied1 = await Deno.copy(Deno.stdout, source);
-   *       const bytesCopied2 = await Deno.copy(buffer, source);
+   *       const bytesCopied1 = await Deno.copy(source, Deno.stdout);
+   *       const bytesCopied2 = await Deno.copy(source, buffer);
    *
    * Because `copy()` is defined to read from `src` until `EOF`, it does not
    * treat an `EOF` from `read()` as an error to be reported.
    *
-   * @param dst The destination to copy to
    * @param src The source to copy from
+   * @param dst The destination to copy to
    */
-  export function copy(dst: Writer, src: Reader): Promise<number>;
+  export function copy(src: Reader, dst: Writer): Promise<number>;
 
   /** Turns a Reader, `r`, into an async iterator.
    *
diff --git a/cli/js/tests/files_test.ts b/cli/js/tests/files_test.ts
index 1e2c06082..11a2e08ae 100644
--- a/cli/js/tests/files_test.ts
+++ b/cli/js/tests/files_test.ts
@@ -18,7 +18,7 @@ unitTest({ perms: { read: true } }, async function filesCopyToStdout(): Promise<
   const filename = "cli/tests/fixture.json";
   const file = await Deno.open(filename);
   assert(file.rid > 2);
-  const bytesWritten = await Deno.copy(Deno.stdout, file);
+  const bytesWritten = await Deno.copy(file, Deno.stdout);
   const fileSize = Deno.statSync(filename).size;
   assertEquals(bytesWritten, fileSize);
   console.log("bytes written", bytesWritten);