fs: fix options.end of fs.ReadStream()

Fixes: #18116
PR-URL: #18121
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Weijia Wang <starkwang@126.com>

Author: 陈刚

lib/fs.js

@@ -1919,7 +1919,8 @@ function ReadStream(path, options) {
 this.flags=options.flags===undefined ? 'r' : options.flags;
 this.mode=options.mode===undefined ? 0o666 : options.mode;
 
-this.start=options.start;
+this.start=typeofthis.fd!=='number'&&options.start===undefined ?
+0 : options.start;
 this.end=options.end;
 this.autoClose=options.autoClose===undefined ? true : options.autoClose;
 this.pos=undefined;

test/parallel/test-fs-read-stream.js

@@ -132,6 +132,20 @@ stream.on('end', function() {
 assert.strictEqual('x',stream.data);
 });
 
+{
+// Verify that end works when start is not specified.
+conststream=newfs.createReadStream(rangeFile,{end: 1});
+stream.data='';
+
+stream.on('data',function(chunk){
+stream.data+=chunk;
+});
+
+stream.on('end',common.mustCall(function(){
+assert.strictEqual('xy',stream.data);
+}));
+}
+
 // pause and then resume immediately.
 constpauseRes=fs.createReadStream(rangeFile);
 pauseRes.pause();