Implementing built in date formatting

internal/number_format/indexed.go

@@ -39,15 +39,15 @@ func init() {
  0x0b: {ml.NumberFormat{ID: 0x0b, Code: `0.00E+00`}, Float},
  0x0c: {ml.NumberFormat{ID: 0x0c, Code: `# ?/?`}, Float},
  0x0d: {ml.NumberFormat{ID: 0x0d, Code: `# ??/??`}, Float},
- 0x0e: {ml.NumberFormat{ID: 0x0e, Code: `m-d-yy`}, Date},
+ 0x0e: {ml.NumberFormat{ID: 0x0e, Code: `d/m/yyyy`}, Date},
  0x0f: {ml.NumberFormat{ID: 0x0f, Code: `d-mmm-yy`}, Date},
  0x10: {ml.NumberFormat{ID: 0x10, Code: `d-mmm`}, Date},
  0x11: {ml.NumberFormat{ID: 0x11, Code: `mmm-yy`}, Date},
  0x12: {ml.NumberFormat{ID: 0x12, Code: `h:mm AM/PM`}, Time},
  0x13: {ml.NumberFormat{ID: 0x13, Code: `h:mm:ss AM/PM`}, Time},
  0x14: {ml.NumberFormat{ID: 0x14, Code: `h:mm`}, Time},
  0x15: {ml.NumberFormat{ID: 0x15, Code: `h:mm:ss`}, Time},
- 0x16: {ml.NumberFormat{ID: 0x16, Code: `m-d-yy h:mm`}, DateTime},
+ 0x16: {ml.NumberFormat{ID: 0x16, Code: `m/d/yy H:mm`}, DateTime},
  //...
  0x25: {ml.NumberFormat{ID: 0x25, Code: `(#,##0_);(#,##0)`}, Integer},
  0x26: {ml.NumberFormat{ID: 0x26, Code: `(#,##0_);[RED](#,##0)`}, Integer},

internal/number_format/types.go

@@ -5,8 +5,11 @@
 package number
 
 import (
+ "strings"
+
  "github.com/plandem/xlsx/internal/ml"
  "github.com/plandem/xlsx/internal/ml/primitives"
+ "github.com/plandem/xlsx/internal/number_format/convert"
 )
 
 //Type of underlying value of built-in number format
@@ -32,6 +35,27 @@
 //LastReservedID is id of last built-in/reserved format
 const LastReservedID = 163
 
+const dateFormatChars = "dmyhH"
+
+type dateFormatMapping struct {
+ excelFormat string
+ goFormat string
+}
+
+// the order of the mapping matters
+var dateFormatParts = []dateFormatMapping{
+ {"d", "02"},
+ {"mmm", "Jan"},
+ {"mm", "04"},
+ {"m", "01"},
+ {"yyyy", "2006"},
+ {"yy", "06"},
+ {"h", "03"},
+ {"H", "15"},
+ {"ss", "05"},
+ {"AM/PM", "PM"},
+}
+
 //New create and return ml.NumberFormat type for provided values, respecting built-in number formats
 func New(id int, code string) ml.NumberFormat {
  return Normalize(ml.NumberFormat{ID: id, Code: code})
@@ -94,6 +118,24 @@
 
 //Format tries to format value into required format code
 func Format(value, code string, t primitives.CellType) string {
+ if strings.ContainsAny(code, dateFormatChars) {
+ return formatDate(value, code)
+ }
+
  //TODO: implement formatting based on code and type
  return value
 }
+
+func formatDate(value, code string) string {
+ dateFormat := code
+ for _, mapping := range dateFormatParts {
+ dateFormat = strings.ReplaceAll(dateFormat, mapping.excelFormat, mapping.goFormat)
+ }
+
+ dateValue, err := convert.ToDate(value)
+ if err != nil {
+ return value
+ }
+
+ return dateValue.UTC().Format(dateFormat)
+}

internal/number_format/types_test.go

@@ -6,6 +6,8 @@ package number
 
 import (
  "github.com/plandem/xlsx/internal/ml"
+ "github.com/plandem/xlsx/internal/ml/primitives"
+ "github.com/stretchr/testify/assert"
  "github.com/stretchr/testify/require"
  "testing"
 )
@@ -44,3 +46,27 @@ func TestNumberFormat(t *testing.T) {
  //custom ID was provided
  require.Equal(t, ml.NumberFormat(ml.NumberFormat{ID: 1000, Code: ""}), New(1000, ""))
 }
+
+func TestDateFormat(t *testing.T) {
+ value := "36892.521"
+ var testCases = []struct {
+ code string
+ expected string
+ }{
+ {"d/m/yyyy", "01/01/2001"},
+ {"d-mmm-yy", "01-Jan-01"},
+ {"d-mmm", "01-Jan"},
+ {"mmm-yy", "Jan-01"},
+ {"h:mm AM/PM", "12:30 PM"},
+ {"h:mm:ss AM/PM", "12:30:14 PM"},
+ {"h:mm", "12:30"},
+ {"h:mm:ss", "12:30:14"},
+ {"m/d/yy H:mm", "01/01/01 12:30"},
+ }
+ for _, test := range testCases {
+ t.Run(test.code, func(t *testing.T) {
+ result := Format(value, test.code, primitives.CellType(0))
+ assert.Equal(t, test.expected, result)
+ })
+ }
+}