diff --git a/lib/fs.js b/lib/fs.js
index 66113899a5bfdc..c6e16a35eec2df 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -67,7 +67,6 @@ const { FSReqCallback, statValues } = binding;
 const { toPathIfFileURL } = require('internal/url');
 const internalUtil = require('internal/util');
 const {
-  copyObject,
   Dirent,
   getDirents,
   getOptions,
@@ -1321,12 +1320,9 @@ function appendFile(path, data, options, callback) {
   callback = maybeCallback(callback || options);
   options = getOptions(options, { encoding: 'utf8', mode: 0o666, flag: 'a' });
 
-  // Don't make changes directly on options object
-  options = copyObject(options);
-
   // Force append behavior when using a supplied file descriptor
   if (!options.flag || isFd(path))
-    options.flag = 'a';
+    options = { ...options, flag: 'a' };
 
   fs.writeFile(path, data, options, callback);
 }
@@ -1334,12 +1330,10 @@ function appendFile(path, data, options, callback) {
 function appendFileSync(path, data, options) {
   options = getOptions(options, { encoding: 'utf8', mode: 0o666, flag: 'a' });
 
-  // Don't make changes directly on options object
-  options = copyObject(options);
-
   // Force append behavior when using a supplied file descriptor
-  if (!options.flag || isFd(path))
-    options.flag = 'a';
+  if (!options.flag || isFd(path)) {
+    options = { ...options, flag: 'a' };
+  }
 
   fs.writeFileSync(path, data, options);
 }
@@ -1348,10 +1342,7 @@ function watch(filename, options, listener) {
   if (typeof options === 'function') {
     listener = options;
   }
-  options = getOptions(options, {});
-
-  // Don't make changes directly on options object
-  options = copyObject(options);
+  options = { ...getOptions(options, {}) };
 
   if (options.persistent === undefined) options.persistent = true;
   if (options.recursive === undefined) options.recursive = false;
diff --git a/lib/internal/fs/promises.js b/lib/internal/fs/promises.js
index 5f8be113f44c0c..896d8025bdaec6 100644
--- a/lib/internal/fs/promises.js
+++ b/lib/internal/fs/promises.js
@@ -25,7 +25,6 @@ const {
 const { isUint8Array } = require('internal/util/types');
 const { rimrafPromises } = require('internal/fs/rimraf');
 const {
-  copyObject,
   getDirents,
   getOptions,
   getStatsFromBinding,
@@ -496,8 +495,9 @@ async function writeFile(path, data, options) {
 
 async function appendFile(path, data, options) {
   options = getOptions(options, { encoding: 'utf8', mode: 0o666, flag: 'a' });
-  options = copyObject(options);
-  options.flag = options.flag || 'a';
+  if (!options.flag) {
+    options = { ...options, flag: 'a' };
+  }
   return writeFile(path, data, options);
 }
 
diff --git a/lib/internal/fs/streams.js b/lib/internal/fs/streams.js
index d1603f6a024b81..c86fb7d3fab4a0 100644
--- a/lib/internal/fs/streams.js
+++ b/lib/internal/fs/streams.js
@@ -20,7 +20,6 @@ const { validateNumber } = require('internal/validators');
 const fs = require('fs');
 const { Buffer } = require('buffer');
 const {
-  copyObject,
   getOptions,
 } = require('internal/fs/utils');
 const { Readable, Writable } = require('stream');
@@ -69,7 +68,7 @@ function ReadStream(path, options) {
     return new ReadStream(path, options);
 
   // A little bit bigger buffer and water marks by default
-  options = copyObject(getOptions(options, {}));
+  options = { ...getOptions(options, {}) };
   if (options.highWaterMark === undefined)
     options.highWaterMark = 64 * 1024;
 
@@ -292,10 +291,8 @@ function WriteStream(path, options) {
   if (!(this instanceof WriteStream))
     return new WriteStream(path, options);
 
-  options = copyObject(getOptions(options, {}));
-
   // Only buffers are supported.
-  options.decodeStrings = true;
+  options = { ...getOptions(options, {}), decodeStrings: true };
 
   // For backwards compat do not emit close on destroy.
   if (options.emitClose === undefined) {
diff --git a/lib/internal/fs/utils.js b/lib/internal/fs/utils.js
index 18d8e07d78e3cb..1c7cda24e0edd8 100644
--- a/lib/internal/fs/utils.js
+++ b/lib/internal/fs/utils.js
@@ -166,49 +166,38 @@ for (const name of ReflectOwnKeys(Dirent.prototype)) {
   };
 }
 
-function copyObject(source) {
-  const target = {};
-  for (const key in source)
-    target[key] = source[key];
-  return target;
-}
-
 function getDirents(path, [names, types], callback) {
-  let i;
-  if (typeof callback === 'function') {
-    const len = names.length;
-    let toFinish = 0;
-    callback = once(callback);
-    for (i = 0; i < len; i++) {
-      const type = types[i];
-      if (type === UV_DIRENT_UNKNOWN) {
-        const name = names[i];
-        const idx = i;
-        toFinish++;
-        lazyLoadFs().lstat(pathModule.join(path, name), (err, stats) => {
-          if (err) {
-            callback(err);
-            return;
-          }
-          names[idx] = new DirentFromStats(name, stats);
-          if (--toFinish === 0) {
-            callback(null, names);
-          }
-        });
-      } else {
-        names[i] = new Dirent(names[i], types[i]);
-      }
-    }
-    if (toFinish === 0) {
-      callback(null, names);
-    }
-  } else {
-    const len = names.length;
-    for (i = 0; i < len; i++) {
+  if (typeof callback !== 'function') {
+    for (let i = 0; i < names.length; i++) {
       names[i] = getDirent(path, names[i], types[i]);
     }
     return names;
   }
+  let toFinish = 0;
+  callback = once(callback);
+  for (let i = 0; i < names.length; i++) {
+    const type = types[i];
+    if (type === UV_DIRENT_UNKNOWN) {
+      const name = names[i];
+      const idx = i;
+      toFinish++;
+      lazyLoadFs().lstat(pathModule.join(path, name), (err, stats) => {
+        if (err) {
+          callback(err);
+          return;
+        }
+        names[idx] = new DirentFromStats(name, stats);
+        if (--toFinish === 0) {
+          callback(null, names);
+        }
+      });
+    } else {
+      names[i] = new Dirent(names[i], types[i]);
+    }
+  }
+  if (toFinish === 0) {
+    callback(null, names);
+  }
 }
 
 function getDirent(path, name, type, callback) {
@@ -239,9 +228,7 @@ function getOptions(options, defaultOptions) {
   }
 
   if (typeof options === 'string') {
-    defaultOptions = { ...defaultOptions };
-    defaultOptions.encoding = options;
-    options = defaultOptions;
+    options = { ...defaultOptions, encoding: options };
   } else if (typeof options !== 'object') {
     throw new ERR_INVALID_ARG_TYPE('options', ['string', 'Object'], options);
   }
@@ -271,13 +258,16 @@ function handleErrorFromBinding(ctx) {
 // Check if the path contains null types if it is a string nor Uint8Array,
 // otherwise return silently.
 const nullCheck = hideStackFrames((path, propName, throwError = true) => {
-  const pathIsString = typeof path === 'string';
-  const pathIsUint8Array = isUint8Array(path);
-
   // We can only perform meaningful checks on strings and Uint8Arrays.
-  if ((!pathIsString && !pathIsUint8Array) ||
-      (pathIsString && !path.includes('\u0000')) ||
-      (pathIsUint8Array && !path.includes(0))) {
+  if (typeof path === 'string') {
+    if (!path.includes('\u0000')) {
+      return;
+    }
+  } else if (isUint8Array(path)) {
+    if (!path.includes(0)) {
+      return;
+    }
+  } else {
     return;
   }
 
@@ -654,7 +644,6 @@ const getValidMode = hideStackFrames((mode, type) => {
 module.exports = {
   assertEncoding,
   BigIntStats,  // for testing
-  copyObject,
   Dirent,
   getDirent,
   getDirents,
diff --git a/test/parallel/test-fs-read-stream-inherit.js b/test/parallel/test-fs-read-stream-inherit.js
deleted file mode 100644
index 5c8bbef0e499c0..00000000000000
--- a/test/parallel/test-fs-read-stream-inherit.js
+++ /dev/null
@@ -1,205 +0,0 @@
-'use strict';
-
-const common = require('../common');
-
-const assert = require('assert');
-const fs = require('fs');
-const fixtures = require('../common/fixtures');
-
-const fn = fixtures.path('elipses.txt');
-const rangeFile = fixtures.path('x.txt');
-
-{
-  let paused = false;
-
-  const file = fs.ReadStream(fn);
-
-  file.on('open', common.mustCall(function(fd) {
-    file.length = 0;
-    assert.strictEqual(typeof fd, 'number');
-    assert.ok(file.readable);
-
-    // GH-535
-    file.pause();
-    file.resume();
-    file.pause();
-    file.resume();
-  }));
-
-  file.on('data', common.mustCallAtLeast(function(data) {
-    assert.ok(data instanceof Buffer);
-    assert.ok(!paused);
-    file.length += data.length;
-
-    paused = true;
-    file.pause();
-
-    setTimeout(function() {
-      paused = false;
-      file.resume();
-    }, 10);
-  }));
-
-
-  file.on('end', common.mustCall());
-
-
-  file.on('close', common.mustCall(function() {
-    assert.strictEqual(file.length, 30000);
-  }));
-}
-
-{
-  const file = fs.createReadStream(fn, Object.create({ encoding: 'utf8' }));
-  file.length = 0;
-  file.on('data', function(data) {
-    assert.strictEqual(typeof data, 'string');
-    file.length += data.length;
-
-    for (let i = 0; i < data.length; i++) {
-      // http://www.fileformat.info/info/unicode/char/2026/index.htm
-      assert.strictEqual(data[i], '\u2026');
-    }
-  });
-
-  file.on('close', common.mustCall(function() {
-    assert.strictEqual(file.length, 10000);
-  }));
-}
-
-{
-  const options = Object.create({ bufferSize: 1, start: 1, end: 2 });
-  const file = fs.createReadStream(rangeFile, options);
-  assert.strictEqual(file.start, 1);
-  assert.strictEqual(file.end, 2);
-  let contentRead = '';
-  file.on('data', function(data) {
-    contentRead += data.toString('utf-8');
-  });
-  file.on('end', common.mustCall(function() {
-    assert.strictEqual(contentRead, 'yz');
-  }));
-}
-
-{
-  const options = Object.create({ bufferSize: 1, start: 1 });
-  const file = fs.createReadStream(rangeFile, options);
-  assert.strictEqual(file.start, 1);
-  file.data = '';
-  file.on('data', function(data) {
-    file.data += data.toString('utf-8');
-  });
-  file.on('end', common.mustCall(function() {
-    assert.strictEqual(file.data, 'yz\n');
-  }));
-}
-
-// https://github.com/joyent/node/issues/2320
-{
-  const options = Object.create({ bufferSize: 1.23, start: 1 });
-  const file = fs.createReadStream(rangeFile, options);
-  assert.strictEqual(file.start, 1);
-  file.data = '';
-  file.on('data', function(data) {
-    file.data += data.toString('utf-8');
-  });
-  file.on('end', common.mustCall(function() {
-    assert.strictEqual(file.data, 'yz\n');
-  }));
-}
-
-{
-  const message =
-    'The value of "start" is out of range. It must be <= "end" (here: 2).' +
-    ' Received 10';
-
-  assert.throws(
-    () => {
-      fs.createReadStream(rangeFile, Object.create({ start: 10, end: 2 }));
-    },
-    {
-      code: 'ERR_OUT_OF_RANGE',
-      message,
-      name: 'RangeError'
-    });
-}
-
-{
-  const options = Object.create({ start: 0, end: 0 });
-  const stream = fs.createReadStream(rangeFile, options);
-  assert.strictEqual(stream.start, 0);
-  assert.strictEqual(stream.end, 0);
-  stream.data = '';
-
-  stream.on('data', function(chunk) {
-    stream.data += chunk;
-  });
-
-  stream.on('end', common.mustCall(function() {
-    assert.strictEqual(stream.data, 'x');
-  }));
-}
-
-// Pause and then resume immediately.
-{
-  const pauseRes = fs.createReadStream(rangeFile);
-  pauseRes.pause();
-  pauseRes.resume();
-}
-
-{
-  let data = '';
-  let file =
-    fs.createReadStream(rangeFile, Object.create({ autoClose: false }));
-  assert.strictEqual(file.autoClose, false);
-  file.on('data', (chunk) => { data += chunk; });
-  file.on('end', common.mustCall(function() {
-    process.nextTick(common.mustCall(function() {
-      assert(!file.closed);
-      assert(!file.destroyed);
-      assert.strictEqual(data, 'xyz\n');
-      fileNext();
-    }));
-  }));
-
-  function fileNext() {
-    // This will tell us if the fd is usable again or not.
-    file = fs.createReadStream(null, Object.create({ fd: file.fd, start: 0 }));
-    file.data = '';
-    file.on('data', function(data) {
-      file.data += data;
-    });
-    file.on('end', common.mustCall(function() {
-      assert.strictEqual(file.data, 'xyz\n');
-    }));
-  }
-  process.on('exit', function() {
-    assert(file.closed);
-    assert(file.destroyed);
-  });
-}
-
-// Just to make sure autoClose won't close the stream because of error.
-{
-  const options = Object.create({ fd: 13337, autoClose: false });
-  const file = fs.createReadStream(null, options);
-  file.on('data', common.mustNotCall());
-  file.on('error', common.mustCall());
-  process.on('exit', function() {
-    assert(!file.closed);
-    assert(!file.destroyed);
-    assert(file.fd);
-  });
-}
-
-// Make sure stream is destroyed when file does not exist.
-{
-  const file = fs.createReadStream('/path/to/file/that/does/not/exist');
-  file.on('data', common.mustNotCall());
-  file.on('error', common.mustCall());
-
-  process.on('exit', function() {
-    assert(!file.closed);
-    assert(file.destroyed);
-  });
-}