Adding Timestamp class

src/document.js

@@ -50,6 +50,11 @@ const DeleteTransform = fieldValue.DeleteTransform;
  */
 const ServerTimestampTransform = fieldValue.ServerTimestampTransform;
 
+/*!
+ * @see {Timestamp}
+ */
+const Timestamp = require('./timestamp');
+
 /*!
  * Injected.
  *
@@ -67,13 +72,6 @@ let validate;
  */
 const MAX_DEPTH = 20;
 
-/*!
- * Number of nanoseconds in a millisecond.
- *
- * @type {number}
- */
-const MS_TO_NANOS = 1000000;
-
 /**
  * An immutable object representing a geographic location in Firestore. The
  * location is represented as a latitude/longitude pair.
@@ -98,8 +96,8 @@ class GeoPoint {
    * });
    */
   constructor(latitude, longitude) {
-    validate.isNumber('latitude', latitude);
-    validate.isNumber('longitude', longitude);
+    validate.isNumber('latitude', latitude, -90, 90);
+    validate.isNumber('longitude', longitude, -180, 180);
 
     this._latitude = latitude;
     this._longitude = longitude;
@@ -532,6 +530,9 @@ class DocumentSnapshot {
    * @returns {*} The converted JS type.
    */
   _decodeValue(proto) {
+    const timestampsInSnapshotsEnabled = this._ref.firestore
+      ._timestampsInSnapshotsEnabled;
+
     switch (proto.valueType) {
       case 'stringValue': {
         return proto.stringValue;
@@ -546,10 +547,11 @@ class DocumentSnapshot {
         return parseFloat(proto.doubleValue, 10);
       }
       case 'timestampValue': {
-        return new Date(
-          (proto.timestampValue.seconds || 0) * 1000 +
-            (proto.timestampValue.nanos || 0) / MS_TO_NANOS
+        const timestamp = new Timestamp(
+          Number(proto.timestampValue.seconds || 0),
+          Number(proto.timestampValue.nanos || 0)
         );
+        return timestampsInSnapshotsEnabled ? timestamp : timestamp.toDate();
       }
       case 'referenceValue': {
         return new DocumentReference(
@@ -733,15 +735,21 @@ class DocumentSnapshot {
       };
     }
 
-    if (is.date(val)) {
-      let epochSeconds = Math.floor(val.getTime() / 1000);
-      let timestamp = {
-        seconds: epochSeconds,
-        nanos: (val.getTime() - epochSeconds * 1000) * MS_TO_NANOS,
+    if (is.instance(val, Timestamp)) {
+      return {
+        valueType: 'timestampValue',
+        timestampValue: {seconds: val.seconds, nanos: val.nanoseconds},
       };
+    }
+
+    if (is.date(val)) {
+      let timestamp = Timestamp.fromDate(val);
       return {
         valueType: 'timestampValue',
-        timestampValue: timestamp,
+        timestampValue: {
+          seconds: timestamp.seconds,
+          nanos: timestamp.nanoseconds,
+        },
       };
     }
 
@@ -1357,7 +1365,7 @@ class DocumentTransform {
    * Returns the array of fields in this DocumentTransform.
    *
    * @private
-   * @type {Array.<FieldPath>} The fields specified in this DocumentTransform.
+   * @type {Array.<FieldPath>}
    * @readonly
    */
   get fields() {
@@ -1550,6 +1558,8 @@ function validateFieldValue(val, options, depth) {
     return true;
   } else if (is.instanceof(val, GeoPoint)) {
     return true;
+  } else if (is.instanceof(val, Timestamp)) {
+    return true;
   } else if (is.instanceof(val, FieldPath)) {
     throw new Error(
       'Cannot use object of type "FieldPath" as a Firestore value.'

src/index.js

@@ -197,6 +197,26 @@ const GRPC_UNAVAILABLE = 14;
 class Firestore {
   /**
    * @param {Object=} options - [Configuration object](#/docs).
+   * @param {string=} options.projectId The Firestore Project ID. Can be
+   * omitted in environments that support `Application Default Credentials`
+   * {@see https://cloud.google.com/docs/authentication}
+   * @param {string=} options.keyFilename Local file containing the Service
+   * Account credentials. Can be omitted in environments that support
+   * `Application Default Credentials`
+   * {@see https://cloud.google.com/docs/authentication}
+   * @param {boolean=} options.timestampsInSnapshots Enables the use of
+   * `Timestamp`s for timestamp fields in `DocumentSnapshots`.<br/>
+   * Currently, Firestore returns timestamp fields as `Date` but `Date` only
+   * supports millisecond precision, which leads to truncation and causes
+   * unexpected behavior when using a timestamp from a snapshot as a part
+   * of a subsequent query.
+   * <br/>Setting `timestampsInSnapshots` to true will cause Firestore to return
+   * `Timestamp` values instead of `Date` avoiding this kind of problem. To
+   * make this work you must also change any code that uses `Date` to use
+   * `Timestamp` instead.
+   * <br/>NOTE: in the future `timestampsInSnapshots: true` will become the
+   * default and this option will be removed so you should change your code to
+   * use `Timestamp` now and opt-in to this new behavior as soon as you can.
    */
   constructor(options) {
     options = extend({}, options, {
@@ -240,6 +260,34 @@ class Firestore {
       Firestore.log('Firestore', 'Detected GCF environment');
     }
 
+    this._timestampsInSnapshotsEnabled = !!options.timestampsInSnapshots;
+
+    if (!this._timestampsInSnapshotsEnabled) {
+      // eslint-disable-next-line no-console
+      console.error(`
+The behavior for Date objects stored in Firestore is going to change
+AND YOUR APP MAY BREAK.
+To hide this warning and ensure your app does not break, you need to add the
+following code to your app before calling any other Cloud Firestore methods:
+
+  const settings = {/* your settings... */ timestampsInSnapshots: true};
+  const firestore = new Firestore(settings);
+
+With this change, timestamps stored in Cloud Firestore will be read back as
+Firebase Timestamp objects instead of as system Date objects. So you will also
+need to update code expecting a Date to instead expect a Timestamp. For example:
+
+  // Old:
+  const date = snapshot.get('created_at');
+  // New:
+  const timestamp = snapshot.get('created_at');
+  const date = timestamp.toDate();
+
+Please audit all existing usages of Date when you enable the new behavior. In a
+future release, the behavior will change to the new behavior, so if you do not
+follow these steps, YOUR APP MAY BREAK.`);
+    }
+
     if (options && options.projectId) {
       validate.isString('options.projectId', options.projectId);
       this._referencePath = new ResourcePath(options.projectId, '(default)');
@@ -1317,3 +1365,12 @@ module.exports.FieldValue = FieldValue;
  * @type {Constructor}
  */
 module.exports.FieldPath = FieldPath;
+
+/**
+ * {@link Timestamp} class.
+ *
+ * @name Firestore.Timestamp
+ * @see Timestamp
+ * @type Timestamp
+ */
+module.exports.Timestamp = require('./timestamp');

src/timestamp.js

@@ -0,0 +1,214 @@
+/*!
+ * Copyright 2018 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+const is = require('is');
+const validate = require('./validate')();
+
+/*!
+ * Number of nanoseconds in a millisecond.
+ *
+ * @type {number}
+ */
+const MS_TO_NANOS = 1000000;
+
+/**
+ * A Timestamp represents a point in time independent of any time zone or
+ * calendar, represented as seconds and fractions of seconds at nanosecond
+ * resolution in UTC Epoch time. It is encoded using the Proleptic Gregorian
+ * Calendar which extends the Gregorian calendar backwards to year one. It is
+ * encoded assuming all minutes are 60 seconds long, i.e. leap seconds are
+ * "smeared" so that no leap second table is needed for interpretation. Range is
+ * from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59.999999999Z.
+ *
+ * @see https://github.com/google/protobuf/blob/master/src/google/protobuf/timestamp.proto
+ */
+class Timestamp {
+  /**
+   * Creates a new timestamp with the current date, with millisecond precision.
+   *
+   * @example
+   * let documentRef = firestore.doc('col/doc');
+   *
+   * documentRef.set({ updateTime:Firestore.Timestamp.now() });
+   *
+   * @return {Timestamp} A new `Timestamp` representing the current date.
+   */
+  static now() {
+    return Timestamp.fromMillis(Date.now());
+  }
+
+  /**
+   * Creates a new timestamp from the given date.
+   *
+   * @example
+   * let documentRef = firestore.doc('col/doc');
+   *
+   * let date = Date.parse('01 Jan 2000 00:00:00 GMT');
+   * documentRef.set({ startTime:Firestore.Timestamp.fromDate(date) });
+   *
+   * @param {Date} date The date to initialize the `Timestamp` from.
+   * @return {Timestamp} A new `Timestamp` representing the same point in time
+   * as the given date.
+   */
+  static fromDate(date) {
+    return Timestamp.fromMillis(date.getTime());
+  }
+
+  /**
+   * Creates a new timestamp from the given number of milliseconds.
+   *
+   * @example
+   * let documentRef = firestore.doc('col/doc');
+   *
+   * documentRef.set({ startTime:Firestore.Timestamp.fromMillis(42) });
+   *
+   * @param {number} milliseconds Number of milliseconds since Unix epoch
+   * 1970-01-01T00:00:00Z.
+   * @return {Timestamp}  A new `Timestamp` representing the same point in time
+   * as the given number of milliseconds.
+   */
+  static fromMillis(milliseconds) {
+    const seconds = Math.floor(milliseconds / 1000);
+    const nanos = (milliseconds - seconds * 1000) * MS_TO_NANOS;
+    return new Timestamp(seconds, nanos);
+  }
+
+  /**
+   * Creates a new timestamp.
+   *
+   * @example
+   * let documentRef = firestore.doc('col/doc');
+   *
+   * documentRef.set({ startTime:new Firestore.Timestamp(42, 0) });
+   *
+   * @param {number} seconds The number of seconds of UTC time since Unix epoch
+   * 1970-01-01T00:00:00Z. Must be from 0001-01-01T00:00:00Z to
+   * 9999-12-31T23:59:59Z inclusive.
+   * @param {number} nanoseconds The non-negative fractions of a second at
+   * nanosecond resolution. Negative second values with fractions must still
+   * have non-negative nanoseconds values that count forward in time. Must be
+   * from 0 to 999,999,999 inclusive.
+   */
+  constructor(seconds, nanoseconds) {
+    validate.isInteger('seconds', seconds);
+    validate.isInteger('nanoseconds', nanoseconds, 0, 999999999);
+
+    this._seconds = seconds;
+    this._nanoseconds = nanoseconds;
+  }
+
+  /**
+   * The number of seconds of UTC time since Unix epoch 1970-01-01T00:00:00Z.
+   *
+   * @example
+   * let documentRef = firestore.doc('col/doc');
+   *
+   * documentRef.get().then(snap => {
+   *   let updatedAt = snap.updateTime;
+   *   console.log(`Updated at ${updated.seconds}s ${updated.nanoseconds}ns`);
+   * });
+   *
+   * @type {number}
+   */
+  get seconds() {
+    return this._seconds;
+  }
+
+  /**
+   * The non-negative fractions of a second at nanosecond resolution.
+   *
+   * @example
+   * let documentRef = firestore.doc('col/doc');
+   *
+   * documentRef.get().then(snap => {
+   *   let updated = snap.updateTime;
+   *   console.log(`Updated at ${updated.seconds}s ${updated.nanoseconds}ns`);
+   * });
+   *
+   * @type {number}
+   */
+  get nanoseconds() {
+    return this._nanoseconds;
+  }
+
+  /**
+   * Returns a new `Date` corresponding to this timestamp. This may lose
+   * precision.
+   *
+   * @example
+   * let documentRef = firestore.doc('col/doc');
+   *
+   * documentRef.get().then(snap => {
+   *   console.log(`Document updated at: ${snap.updateTime.toDate()}`);
+   * });
+   *
+   * @return {Date} JavaScript `Date` object representing the same point in time
+   * as this `Timestamp`, with millisecond precision.
+   */
+  toDate() {
+    return new Date(
+      this._seconds * 1000 + Math.round(this._nanoseconds / MS_TO_NANOS)
+    );
+  }
+
+  /**
+   * Returns the number of milliseconds since Unix epoch 1970-01-01T00:00:00Z.
+   *
+   * @example
+   * let documentRef = firestore.doc('col/doc');
+   *
+   * documentRef.get().then(snap => {
+   *   let startTime = snap.get('startTime');
+   *   let endTime = snap.get('endTime');
+   *   console.log(`Duration: ${endTime - startTime}`);
+   * });
+   *
+   * @return {number} The point in time corresponding to this timestamp,
+   * represented as the number of milliseconds since Unix epoch
+   * 1970-01-01T00:00:00Z.
+   */
+  toMillis() {
+    return this._seconds * 1000 + Math.floor(this._nanoseconds / MS_TO_NANOS);
+  }
+
+  /**
+   * Returns 'true' if this `Timestamp` is equal to the provided one.
+   *
+   * @example
+   * let documentRef = firestore.doc('col/doc');
+   *
+   * documentRef.get().then(snap => {
+   *   if (snap.createTime.isEqual(snap.updateTime)) {
+   *     console.log('Document is in its initial state.');
+   *   }
+   * });
+   *
+   * @param {any} other The `Timestamp` to compare against.
+   * @return {boolean} 'true' if this `Timestamp` is equal to the provided one.
+   */
+  isEqual(other) {
+    return (
+      this === other ||
+      (is.instanceof(other, Timestamp) &&
+        this._seconds === other.seconds &&
+        this._nanoseconds === other.nanoseconds)
+    );
+  }
+}
+
+module.exports = Timestamp;