Fix parseDate, consider DST

src/scale/Time.js

@@ -77,7 +77,7 @@ define(function (require) {
             // If there are no data and extent are [Infinity, -Infinity]
             if (extent[1] === -Infinity && extent[0] === Infinity) {
                 var d = new Date();
-                extent[1] = new Date(d.getFullYear(), d.getMonth(), d.getDate());
+                extent[1] = +new Date(d.getFullYear(), d.getMonth(), d.getDate());
                 extent[0] = extent[1] - ONE_DAY;
             }
 
@@ -98,8 +98,6 @@ define(function (require) {
          * @override
          */
         niceTicks: function (approxTickNum, minInterval, maxInterval) {
-            var timezoneOffset = this.getSetting('useUTC')
-                ? 0 : numberUtil.getTimezoneOffset() * 60 * 1000;
             approxTickNum = approxTickNum || 10;
 
             var extent = this._extent;
@@ -129,9 +127,11 @@ define(function (require) {
                 interval *= yearStep;
             }
 
+            var timezoneOffset = this.getSetting('useUTC')
+                ? 0 : (new Date(+extent[0] || +extent[1])).getTimezoneOffset() * 60 * 1000;
             var niceExtent = [
                 Math.round(mathCeil((extent[0] - timezoneOffset) / interval) * interval + timezoneOffset),
-                Math.round(mathFloor((extent[1] - timezoneOffset)/ interval) * interval + timezoneOffset)
+                Math.round(mathFloor((extent[1] - timezoneOffset) / interval) * interval + timezoneOffset)
             ];
 
             scaleHelper.fixExtent(niceExtent, extent);

src/util/number.js

@@ -273,11 +273,14 @@ define(function (require) {
     var TIME_REG = /^(?:(\d{4})(?:[-\/](\d{1,2})(?:[-\/](\d{1,2})(?:[T ](\d{1,2})(?::(\d\d)(?::(\d\d)(?:[.,](\d+))?)?)?(Z|[\+\-]\d\d:?\d\d)?)?)?)?)?$/; // jshint ignore:line
 
     /**
+     * Consider DST, it is incorrect to provide a method `getTimezoneOffset`
+     * without time specified. So this method is removed.
+     *
      * @return {number} in minutes
      */
-    number.getTimezoneOffset = function () {
-        return (new Date()).getTimezoneOffset();
-    };
+    // number.getTimezoneOffset = function () {
+    //     return (new Date()).getTimezoneOffset();
+    // };
 
     /**
      * @param {string|Date|number} value These values can be accepted:
@@ -311,24 +314,42 @@ define(function (require) {
                 return new Date(NaN);
             }
 
-            var timezoneOffset = number.getTimezoneOffset();
-            var timeOffset = !match[8]
-                ? 0
-                : match[8].toUpperCase() === 'Z'
-                ? timezoneOffset
-                : +match[8].slice(0, 3) * 60 + timezoneOffset;
-
-            // match[n] can only be string or undefined.
-            // But take care of '12' + 1 => '121'.
-            return new Date(
-                +match[1],
-                +(match[2] || 1) - 1,
-                +match[3] || 1,
-                +match[4] || 0,
-                +(match[5] || 0) - timeOffset,
-                +match[6] || 0,
-                +match[7] || 0
-            );
+            // Use local time when no timezone offset specifed.
+            if (!match[8]) {
+                // match[n] can only be string or undefined.
+                // But take care of '12' + 1 => '121'.
+                return new Date(
+                    +match[1],
+                    +(match[2] || 1) - 1,
+                    +match[3] || 1,
+                    +match[4] || 0,
+                    +(match[5] || 0),
+                    +match[6] || 0,
+                    +match[7] || 0
+                );
+            }
+            // Timezoneoffset of Javascript Date has considered DST (Daylight Saving Time,
+            // https://tc39.github.io/ecma262/#sec-daylight-saving-time-adjustment).
+            // For example, system timezone is set as "Time Zone: America/Toronto",
+            // then these code will get different result:
+            // `new Date(1478411999999).getTimezoneOffset();  // get 240`
+            // `new Date(1478412000000).getTimezoneOffset();  // get 300`
+            // So we should not use `new Date`, but use `Date.UTC`.
+            else {
+                var hour = +match[4] || 0;
+                if (match[8].toUpperCase() !== 'Z') {
+                    hour -= match[8].slice(0, 3);
+                }
+                return new Date(Date.UTC(
+                    +match[1],
+                    +(match[2] || 1) - 1,
+                    +match[3] || 1,
+                    hour,
+                    +(match[5] || 0),
+                    +match[6] || 0,
+                    +match[7] || 0
+                ));
+            }
         }
         else if (value == null) {
             return new Date(NaN);

test/timeZone.html

@@ -22,10 +22,10 @@
         </style>
 
 
-        <h1>time scale label shoule in local time when timestamp (in UTC) input, tick should align with day.</h1>
+        <h1>time scale label should in local time when timestamp (in UTC) input, tick should align with day.</h1>
         <div class="chart" id="chart0"></div>
 
-        <h1>time scale label shoule in UTC time when option.useUTC is `true`, tick should not align with day.</h1>
+        <h1>time scale label should in UTC time when option.useUTC is `true`, tick should not align with day.</h1>
         <div class="chart" id="chart1"></div>
 
         <h1>useUTC: null, should display '00:00 01-03' in tooltip on the 1st point</h1>