Simplify date handling (#119)

BREAKING

The binary parser’s approach of creating a local timestamp then adjusting it by its timezone offset to get the same components in UTC just doesn’t work, producing the wrong results around daylight saving transitions, for example. But even when it’s fixed to work as well as the text parser does, some times are still completely unrepresentable because they don’t exist in local time (daylight saving transitions are, again, an example of this). The more reliable way is:

- `timestamptz` represents an instant in time
- `timestamp` preserves its components in UTC
- `date` remains a string

* Round to nearest millisecond in binary timestamp parser

to match the new postgres-date@1.0.5 behavior, compared to 1.0.4.

lib/binaryParsers.js

@@ -17,27 +17,11 @@ var parseFloat64 = function (value) {
   return value.readDoubleBE(0)
 }
 
-var parseDate = function (isUTC, value) {
+var parseTimestampUTC = function (value) {
   var rawValue = 0x100000000 * value.readInt32BE(0) + value.readUInt32BE(4)
 
   // discard usecs and shift from 2000 to 1970
-  var result = new Date((rawValue / 1000) + 946684800000)
-
-  if (!isUTC) {
-    result.setTime(result.getTime() + result.getTimezoneOffset() * 60000)
-  }
-
-  // add microseconds to the date
-  result.usec = rawValue % 1000
-  result.getMicroSeconds = function () {
-    return this.usec
-  }
-  result.setMicroSeconds = function (value) {
-    this.usec = value
-  }
-  result.getUTCMicroSeconds = function () {
-    return this.usec
-  }
+  var result = new Date(Math.round(rawValue / 1000) + 946684800000)
 
   return result
 }
@@ -127,8 +111,8 @@ var init = function (register) {
   register(700, parseFloat32)
   register(701, parseFloat64)
   register(16, parseBool)
-  register(1114, parseDate.bind(null, false))
-  register(1184, parseDate.bind(null, true))
+  register(1114, parseTimestampUTC)
+  register(1184, parseTimestampUTC)
   register(1000, parseArray)
   register(1007, parseArray)
   register(1016, parseArray)

lib/textParsers.js

@@ -1,5 +1,5 @@
 var array = require('postgres-array')
-var parseTimestamp = require('postgres-date')
+var parseTimestampTz = require('postgres-date')
 var parseInterval = require('postgres-interval')
 var parseByteA = require('postgres-bytea')
 
@@ -50,16 +50,27 @@ var parseStringArray = function (value) {
   return array.parse(value, undefined)
 }
 
-var parseIntervalArray = function (value) {
-  if (!value) { return null }
-  return array.parse(value, parseInterval)
+var parseTimestamp = function (value) {
+  var utc = value.endsWith(' BC')
+    ? value.slice(0, -3) + 'Z BC'
+    : value + 'Z'
+
+  return parseTimestampTz(utc)
 }
 
 var parseTimestampArray = function (value) {
-  if (!value) { return null }
   return array.parse(value, parseTimestamp)
 }
 
+var parseTimestampTzArray = function (value) {
+  return array.parse(value, parseTimestampTz)
+}
+
+var parseIntervalArray = function (value) {
+  if (!value) { return null }
+  return array.parse(value, parseInterval)
+}
+
 var parseByteAArray = function (value) {
   if (!value) { return null }
   return array.parse(value, parseByteA)
@@ -125,8 +136,8 @@ var init = function (register) {
   register(700, parseFloat) // float4/real
   register(701, parseFloat) // float8/double
   register(16, parseBool)
-  register(1114, parseTimestamp) // timestamp without timezone
-  register(1184, parseTimestamp) // timestamp
+  register(1114, parseTimestamp) // timestamp without time zone
+  register(1184, parseTimestampTz) // timestamp with time zone
   register(600, parsePoint) // point
   register(651, parseStringArray) // cidr[]
   register(718, parseCircle) // circle
@@ -147,8 +158,8 @@ var init = function (register) {
   register(1040, parseStringArray) // macaddr[]
   register(1041, parseStringArray) // inet[]
   register(1115, parseTimestampArray) // timestamp without time zone[]
-  register(1182, parseStringArray) // _date
-  register(1185, parseTimestampArray) // timestamp with time zone[]
+  register(1182, parseStringArray) // date[]
+  register(1185, parseTimestampTzArray) // timestamp with time zone[]
   register(1186, parseInterval)
   register(1187, parseIntervalArray)
   register(17, parseByteA)

test/types.js

@@ -100,6 +100,10 @@ exports.timestamptz = {
     [
       '2010-10-30 13:10:01+05',
       dateEquals(2010, 9, 30, 8, 10, 1, 0)
+    ],
+    [
+      '1000-01-01 00:00:00+00 BC',
+      dateEquals(-999, 0, 1, 0, 0, 0, 0)
     ]
   ]
 }
@@ -112,12 +116,17 @@ exports.timestamp = {
       '2010-10-31 00:00:00',
       function (t, value) {
         t.equal(
-          value.toUTCString(),
-          new Date(2010, 9, 31, 0, 0, 0, 0).toUTCString()
+          value.toISOString(),
+          '2010-10-31T00:00:00.000Z'
         )
+      }
+    ],
+    [
+      '1000-01-01 00:00:00 BC',
+      function (t, value) {
         t.equal(
-          value.toString(),
-          new Date(2010, 9, 31, 0, 0, 0, 0).toString()
+          value.toISOString(),
+          '-000999-01-01T00:00:00.000Z'
         )
       }
     ]
@@ -128,7 +137,8 @@ exports.date = {
   format: 'text',
   id: 1082,
   tests: [
-    ['2010-10-31', '2010-10-31']
+    ['2010-10-31', '2010-10-31'],
+    ['2010-10-31 BC', '2010-10-31 BC']
   ]
 }