fs: expose Stats times as Numbers

This also reverts commit 9836cf5.

Fixes: npm/npm#16734
Ref: #12607
Ref: #12818

Author: refack

doc/api/fs.md

@@ -295,10 +295,14 @@ argument to `fs.createReadStream()`. If `path` is passed as a string, then
 ## Class: fs.Stats
 <!-- YAML
 added: v0.1.21
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/13173
+    description: Added times as numbers.
 -->
 
-Objects returned from [`fs.stat()`][], [`fs.lstat()`][] and [`fs.fstat()`][] and their
-synchronous counterparts are of this type.
+Objects returned from [`fs.stat()`][], [`fs.lstat()`][] and [`fs.fstat()`][] and
+their synchronous counterparts are of this type.
 
  - `stats.isFile()`
  - `stats.isDirectory()`
@@ -323,20 +327,22 @@ Stats {
   size: 527,
   blksize: 4096,
   blocks: 8,
+  atimeMs: 1318289051000.1,
+  mtimeMs: 1318289051000.1,
+  ctimeMs: 1318289051000.1,
+  birthtimeMs: 1318289051000.1,
   atime: Mon, 10 Oct 2011 23:24:11 GMT,
   mtime: Mon, 10 Oct 2011 23:24:11 GMT,
   ctime: Mon, 10 Oct 2011 23:24:11 GMT,
   birthtime: Mon, 10 Oct 2011 23:24:11 GMT }
 ```
 
-Please note that `atime`, `mtime`, `birthtime`, and `ctime` are
-instances of [`Date`][MDN-Date] object and appropriate methods should be used
-to compare the values of these objects. For most general uses
-[`getTime()`][MDN-Date-getTime] will return the number of milliseconds elapsed
-since _1 January 1970 00:00:00 UTC_ and this integer should be sufficient for
-any comparison, however there are additional methods which can be used for
-displaying fuzzy information. More details can be found in the
-[MDN JavaScript Reference][MDN-Date] page.
+*Note*: `atimeMs`, `mtimeMs`, `ctimeMs`, `birthtimeMs` are [numbers][MDN-Number]
+that hold the corresponding times in milliseconds. Their precision is platform
+specific. `atime`, `mtime`, `ctime`, and `birthtime` are [`Date`][MDN-Date]
+object alternate representations of the various times. The `Date` and number
+values are not connected. Assigning a new number value, or mutating the `Date`
+value, will not be reflected in the corresponding alternate representation.
 
 ### Stat Time Values
 
@@ -527,7 +533,7 @@ The "not recommended" examples above check for accessibility and then use the
 file; the "recommended" examples are better because they use the file directly
 and handle the error, if any.
 
-In general, check for the accessibility of a file only if the file won’t be
+In general, check for the accessibility of a file only if the file won't be
 used directly, for example when its accessibility is a signal from another
 process.
 
@@ -959,7 +965,7 @@ The "not recommended" examples above check for existence and then use the
 file; the "recommended" examples are better because they use the file directly
 and handle the error, if any.
 
-In general, check for the existence of a file only if the file won’t be
+In general, check for the existence of a file only if the file won't be
 used directly, for example when its existence is a signal from another
 process.
 

lib/fs.js

@@ -196,81 +196,17 @@ function Stats(
   this.ino = ino;
   this.size = size;
   this.blocks = blocks;
-  this._atim_msec = atim_msec;
-  this._mtim_msec = mtim_msec;
-  this._ctim_msec = ctim_msec;
-  this._birthtim_msec = birthtim_msec;
+  this.atimeMs = atim_msec;
+  this.mtimeMs = mtim_msec;
+  this.ctimeMs = ctim_msec;
+  this.birthtimeMs = birthtim_msec;
+  this.atime = new Date(atim_msec);
+  this.mtime = new Date(mtim_msec);
+  this.ctime = new Date(ctim_msec);
+  this.birthtime = new Date(birthtim_msec);
 }
 fs.Stats = Stats;
 
-// defining the properties in this fashion (explicitly with no loop or factory)
-// has been shown to be the most performant on V8 contemp.
-// Ref: https://github.com/nodejs/node/pull/12818
-// + 0.5 is added to the Dates to protect values from being rounded down
-// Ref: https://github.com/nodejs/node/pull/12607
-Object.defineProperties(Stats.prototype, {
-  atime: {
-    configurable: true,
-    enumerable: true,
-    get() {
-      return this._atime !== undefined ?
-          this._atime :
-          (this._atime = new Date(this._atim_msec + 0.5));
-    },
-    set(value) { return this._atime = value; }
-  },
-  mtime: {
-    configurable: true,
-    enumerable: true,
-    get() {
-      return this._mtime !== undefined ?
-          this._mtime :
-          (this._mtime = new Date(this._mtim_msec + 0.5));
-    },
-    set(value) { return this._mtime = value; }
-  },
-  ctime: {
-    configurable: true,
-    enumerable: true,
-    get() {
-      return this._ctime !== undefined ?
-        this._ctime :
-        (this._ctime = new Date(this._ctim_msec + 0.5));
-    },
-    set(value) { return this._ctime = value; }
-  },
-  birthtime: {
-    configurable: true,
-    enumerable: true,
-    get() {
-      return this._birthtime !== undefined ?
-        this._birthtime :
-        (this._birthtime = new Date(this._birthtim_msec + 0.5));
-    },
-    set(value) { return this._birthtime = value; }
-  },
-});
-
-Stats.prototype.toJSON = function toJSON() {
-  return {
-    dev: this.dev,
-    mode: this.mode,
-    nlink: this.nlink,
-    uid: this.uid,
-    gid: this.gid,
-    rdev: this.rdev,
-    blksize: this.blksize,
-    ino: this.ino,
-    size: this.size,
-    blocks: this.blocks,
-    atime: this.atime,
-    ctime: this.ctime,
-    mtime: this.mtime,
-    birthtime: this.birthtime
-  };
-};
-
-
 Stats.prototype._checkModeProperty = function(property) {
   return ((this.mode & S_IFMT) === property);
 };

test/parallel/test-fs-stat.js

@@ -65,60 +65,55 @@ fs.open('.', 'r', undefined, common.mustCall(function(err, fd) {
     assert.fail(err);
   }
   if (stats) {
-    console.dir(stats);
     assert.ok(stats.mtime instanceof Date);
   }
   fs.close(fd, assert.ifError);
 }));
 
-console.log(`stating:  ${__filename}`);
 fs.stat(__filename, common.mustCall(function(err, s) {
   assert.ifError(err);
-
-  console.dir(s);
-
-  console.log(`isDirectory: ${JSON.stringify(s.isDirectory())}`);
   assert.strictEqual(false, s.isDirectory());
-
-  console.log(`isFile: ${JSON.stringify(s.isFile())}`);
   assert.strictEqual(true, s.isFile());
-
-  console.log(`isSocket: ${JSON.stringify(s.isSocket())}`);
   assert.strictEqual(false, s.isSocket());
-
-  console.log(`isBlockDevice: ${JSON.stringify(s.isBlockDevice())}`);
   assert.strictEqual(false, s.isBlockDevice());
-
-  console.log(`isCharacterDevice: ${JSON.stringify(s.isCharacterDevice())}`);
   assert.strictEqual(false, s.isCharacterDevice());
-
-  console.log(`isFIFO: ${JSON.stringify(s.isFIFO())}`);
   assert.strictEqual(false, s.isFIFO());
-
-  console.log(`isSymbolicLink: ${JSON.stringify(s.isSymbolicLink())}`);
   assert.strictEqual(false, s.isSymbolicLink());
-
-  assert.ok(s.atime instanceof Date);
-  assert.ok(s.mtime instanceof Date);
-  assert.ok(s.ctime instanceof Date);
-  assert.ok(s.birthtime instanceof Date);
-}));
-
-fs.stat(__filename, common.mustCall(function(err, s) {
-  const json = JSON.parse(JSON.stringify(s));
   const keys = [
     'dev', 'mode', 'nlink', 'uid',
-    'gid', 'rdev', 'ino',
-    'size', 'atime', 'mtime',
-    'ctime', 'birthtime'
+    'gid', 'rdev', 'ino', 'size',
+    'atimeMs', 'mtimeMs', 'ctimeMs', 'birthtimeMs',
+    'atime', 'mtime', 'ctime', 'birthtime'
+  ];
+  const dateFields = [ 'atime', 'mtime', 'ctime', 'birthtime' ];
+  const numberFields = [
+    'dev', 'mode', 'nlink', 'uid', 'gid', 'rdev', 'ino', 'size',
+    'atimeMs', 'mtimeMs', 'ctimeMs', 'birthtimeMs'
   ];
   if (!common.isWindows) {
     keys.push('blocks', 'blksize');
+    numberFields.push('blocks', 'blksize');
   }
+  const actualKeys = Object.keys(s);
+  keys.forEach((k) => assert.strictEqual(actualKeys.includes(k), true,
+                                         `${k} should a field of s`));
+  numberFields.forEach((k) => {
+    assert.strictEqual(typeof s[k], 'number', `${k} should be a number`);
+  });
+  dateFields.forEach((k) => {
+    assert.ok(s[k] instanceof Date, `${k} should be a Date`);
+  });
+  const parsed = JSON.parse(JSON.stringify(s));
   keys.forEach(function(k) {
     assert.ok(
-      json[k] !== undefined && json[k] !== null,
+      parsed[k] !== undefined && parsed[k] !== null,
       k + ' should not be null or undefined'
     );
   });
+  numberFields.forEach((k) => {
+    assert.strictEqual(typeof parsed[k], 'number', `${k} should be a number`);
+  });
+  dateFields.forEach((k) => {
+    assert.strictEqual(typeof parsed[k], 'string', `${k} should be a string`);
+  });
 }));