Test exporting datetime values as strings with sub-millisecond precision

.changeset/spotty-buckets-flash.md

@@ -0,0 +1,5 @@
+---
+'@powersync/mysql-zongji': minor
+---
+
+Export date and time values as structured fields.

README.md

@@ -75,8 +75,6 @@ The `ZongJi` constructor accepts one argument of either:
 
 If a `Connection` or `Pool` object is passed to the constructor, it will not be destroyed/ended by Zongji's `stop()` method.
 
-If there is a `dateStrings` `mysql` configuration option in the connection details or connection, `ZongJi` will follow it.
-
 Each instance includes the following methods:
 
 | Method Name | Arguments              | Description                                                                                  |
@@ -139,7 +137,6 @@ Neither method requires any arguments.
 - :star2: [All types allowed by `mysql`](https://github.com/mysqljs/mysql#type-casting) are supported by this package.
 - :speak_no_evil: 64-bit integer is supported via package big-integer(see #108). If an integer is within the safe range of JS number (-2^53, 2^53), a Number object will returned, otherwise, will return as String.
 - :point_right: `TRUNCATE` statement does not cause corresponding `DeleteRows` event. Use unqualified `DELETE FROM` for same effect.
-- When using fractional seconds with `DATETIME` and `TIMESTAMP` data types in MySQL > 5.6.4, only millisecond precision is available due to the limit of Javascript's `Date` object.
 
 ## Run Tests
 

lib/common.js

@@ -1,6 +1,5 @@
 const iconv = require('iconv-lite');
 const decodeJson = require('./json_decode');
-const dtDecode = require('./datetime_decode');
 const bigInt = require('big-integer');
 
 const MysqlTypes = (exports.MysqlTypes = {
@@ -332,27 +331,14 @@ const parseGeometryValue = function (buffer) {
 // Returns false, or an object describing the fraction of a second part of a
 // TIME, DATETIME, or TIMESTAMP.
 const readTemporalFraction = function (parser, fractionPrecision) {
-  if (!fractionPrecision) return false;
+  if (!fractionPrecision) return undefined;
   let fractionSize = Math.ceil(fractionPrecision / 2);
   let fraction = readIntBE(parser._buffer, parser._offset, fractionSize);
   parser._offset += fractionSize;
   if (fractionPrecision % 2 !== 0) fraction /= 10; // Not using full space
   if (fraction < 0) fraction *= -1; // Negative time, fraction not negative
 
-  let milliseconds;
-  if (fractionPrecision > 3) {
-    milliseconds = Math.floor(fraction / Math.pow(10, fractionPrecision - 3));
-  } else if (fractionPrecision < 3) {
-    milliseconds = fraction * Math.pow(10, 3 - fractionPrecision);
-  } else {
-    milliseconds = fraction;
-  }
-
-  return {
-    value: fraction, // the integer after the decimal place
-    precision: fractionPrecision, // the number of digits after the decimal
-    milliseconds: milliseconds // the unrounded 3 digits after the decimal
-  };
+  return { fraction, precision: fractionPrecision };
 };
 
 // This function is used to read and interpret non-null values from parser.
@@ -485,12 +471,12 @@ exports.readMysqlValue = function (
       break;
     case MysqlTypes.DATE:
       raw = parseUInt24(parser);
-      result = dtDecode.getDate(
-        zongji.connection.config.dateStrings, // node-mysql dateStrings option
-        sliceBits(raw, 9, 24), // year
-        sliceBits(raw, 5, 9), // month
-        sliceBits(raw, 0, 5) // day
-      );
+
+      result = {
+        year: sliceBits(raw, 9, 24),
+        month: sliceBits(raw, 5, 9),
+        day: sliceBits(raw, 0, 5)
+      };
       break;
     case MysqlTypes.TIME:
       raw = parseUInt24(parser);
@@ -523,35 +509,31 @@ exports.readMysqlValue = function (
       minute = sliceBits(raw, 6, 12);
       second = sliceBits(raw, 0, 6);
 
-      if (isNegative && (fraction === false || fraction.value === 0)) {
+      if (isNegative && (fraction === undefined || fraction.value === 0)) {
         second++;
       }
 
-      result =
-        (isNegative ? '-' : '') +
-        zeroPad(hour, hour > 99 ? 3 : 2) +
-        ':' +
-        zeroPad(minute, 2) +
-        ':' +
-        zeroPad(second, 2);
+      result = {
+        isNegative,
+        hour,
+        minute,
+        second,
+        fraction
+      };
 
-      if (fraction !== false) {
-        result += dtDecode.getFractionString(fraction);
-      }
       break;
     case MysqlTypes.DATETIME:
       raw = parseUInt64(parser);
       date = Math.floor(raw / 1000000);
       time = raw % 1000000;
-      result = dtDecode.getDateTime(
-        zongji.connection.config.dateStrings, // node-mysql dateStrings option
-        Math.floor(date / 10000), // year
-        Math.floor((date % 10000) / 100), // month
-        date % 100, // day
-        Math.floor(time / 10000), // hour
-        Math.floor((time % 10000) / 100), // minutes
-        time % 100 // seconds
-      );
+      result = {
+        year: Math.floor(date / 10000),
+        month: Math.floor((date % 10000) / 100),
+        day: date % 100,
+        hour: Math.floor(time / 10000),
+        minute: Math.floor((time % 10000) / 100),
+        second: time % 100
+      };
       break;
     case MysqlTypes.DATETIME2: {
       // Overlapping high-low to get all data in 32-bit numbers
@@ -561,31 +543,30 @@ exports.readMysqlValue = function (
       fraction = readTemporalFraction(parser, column.metadata.decimals);
 
       yearMonth = sliceBits(rawHigh, 14, 31);
-      result = dtDecode.getDateTime(
-        zongji.connection.config.dateStrings, // node-mysql dateStrings option
-        Math.floor(yearMonth / 13), // year
-        yearMonth % 13, // month
-        sliceBits(rawLow, 17, 22), // day
-        sliceBits(rawLow, 12, 17), // hour
-        sliceBits(rawLow, 6, 12), // minutes
-        sliceBits(rawLow, 0, 6), // seconds
-        fraction // fraction of a second object
-      );
+      result = {
+        year: Math.floor(yearMonth / 13),
+        month: yearMonth % 13,
+        day: sliceBits(rawLow, 17, 22),
+        hour: sliceBits(rawLow, 12, 17),
+        minute: sliceBits(rawLow, 6, 12),
+        second: sliceBits(rawLow, 0, 6),
+        fraction
+      };
       break;
     }
     case MysqlTypes.TIMESTAMP:
       raw = parser.parseUnsignedNumber(4);
-      result = dtDecode.getTimeStamp(zongji.connection.config.dateStrings, raw);
+      result = {
+        secondsFromEpoch: raw
+      };
       break;
     case MysqlTypes.TIMESTAMP2:
       raw = readIntBE(parser._buffer, parser._offset, 4);
       parser._offset += 4;
-      fraction = readTemporalFraction(parser, column.metadata.decimals);
-      result = dtDecode.getTimeStamp(
-        zongji.connection.config.dateStrings,
-        raw, // seconds from epoch
-        fraction
-      ); // fraction of a second object
+      result = {
+        secondsFromEpoch: raw,
+        fraction: readTemporalFraction(parser, column.metadata.decimals)
+      };
       break;
     case MysqlTypes.YEAR:
       raw = parser.parseUnsignedNumber(1);