Enable defining a new date format for reports. (#165)

# Describe Request

Enable defining a new date format for reports. 

Fixed #158 

# Change Type

New feature.

Author: cinar

cmd/indicator-backtest/main.go

@@ -12,6 +12,7 @@ import (
 	"os"
 
 	"github.com/cinar/indicator/v2/asset"
+	"github.com/cinar/indicator/v2/helper"
 	"github.com/cinar/indicator/v2/strategy"
 	"github.com/cinar/indicator/v2/strategy/compound"
 	"github.com/cinar/indicator/v2/strategy/momentum"
@@ -27,6 +28,7 @@ func main() {
 	var writeStrategyRerpots bool
 	var addSplits bool
 	var addAnds bool
+	var dateFormat string
 
 	fmt.Fprintln(os.Stderr, "Indicator Backtest")
 	fmt.Fprintln(os.Stderr, "Copyright (c) 2021-2024 Onur Cinar.")
@@ -41,6 +43,7 @@ func main() {
 	flag.BoolVar(&writeStrategyRerpots, "write-strategy-reports", strategy.DefaultWriteStrategyReports, "write individual strategy reports")
 	flag.BoolVar(&addSplits, "splits", false, "add the split strategies")
 	flag.BoolVar(&addAnds, "ands", false, "add the and strategies")
+	flag.StringVar(&dateFormat, "date-format", helper.DefaultReportDateFormat, "date format to use")
 	flag.Parse()
 
 	flag.Parse()
@@ -51,6 +54,7 @@ func main() {
 	backtest.Workers = workers
 	backtest.LastDays = lastDays
 	backtest.WriteStrategyReports = writeStrategyRerpots
+	backtest.DateFormat = dateFormat
 	backtest.Names = append(backtest.Names, flag.Args()...)
 	backtest.Strategies = append(backtest.Strategies, compound.AllStrategies()...)
 	backtest.Strategies = append(backtest.Strategies, momentum.AllStrategies()...)

helper/report.go

@@ -17,6 +17,11 @@ import (
 //go:embed "report.tmpl"
 var reportTmpl string
 
+const (
+	// DefaultReportDateFormat is the default date format used in the report.
+	DefaultReportDateFormat = "2006-01-02"
+)
+
 // ReportColumn defines the interface that all report data columns must implement.
 // This interface ensures that different types of data columns can be used
 // consistently within the report generation process.
@@ -34,62 +39,55 @@ type ReportColumn interface {
 	Value() string
 }
 
-// reportModel struct holds the data that is exposed to the template renderer
-// for generating the report. It encapsulates all the information necessary
-// to render the report's content, including data, and annotations.
-type reportModel struct {
-	Title   string
-	Date    <-chan time.Time
-	Columns []ReportColumn
-	Views   [][]int
-}
-
 // Report generates an HTML file containing an interactive chart that
 // visually represents the provided data and annotations.
 //
 // The generated HTML file can be opened in a web browser to explore
 // the data visually, interact with the chart elements, and view
 // the associated annotations.
 type Report struct {
-	model reportModel
+	Title      string
+	Date       <-chan time.Time
+	Columns    []ReportColumn
+	Views      [][]int
+	DateFormat string
 }
 
 // NewReport takes a channel of time as the time axis and returns a new
 // instance of the Report struct. This instance can later be used to
 // add data and annotations and subsequently generate a report.
 func NewReport(title string, date <-chan time.Time) *Report {
 	return &Report{
-		model: reportModel{
-			Title:   title,
-			Date:    date,
-			Columns: []ReportColumn{},
-			Views: [][]int{
-				{},
-			},
+		Title:   title,
+		Date:    date,
+		Columns: []ReportColumn{},
+		Views: [][]int{
+			{},
 		},
+		DateFormat: DefaultReportDateFormat,
 	}
 }
 
 // AddChart adds a new chart to the report and returns its unique
 // identifier. This identifier can be used later to refer to the
 // chart and add columns to it.
 func (r *Report) AddChart() int {
-	r.model.Views = append(r.model.Views, []int{})
-	return len(r.model.Views) - 1
+	r.Views = append(r.Views, []int{})
+	return len(r.Views) - 1
 }
 
 // AddColumn adds a new data column to the specified charts. If no
 // chart is specified, it will be added to the main chart.
 func (r *Report) AddColumn(column ReportColumn, charts ...int) {
-	r.model.Columns = append(r.model.Columns, column)
-	columnID := len(r.model.Columns)
+	r.Columns = append(r.Columns, column)
+	columnID := len(r.Columns)
 
 	if len(charts) == 0 {
 		charts = append(charts, 0)
 	}
 
 	for _, chartID := range charts {
-		r.model.Views[chartID] = append(r.model.Views[chartID], columnID)
+		r.Views[chartID] = append(r.Views[chartID], columnID)
 	}
 }
 
@@ -102,7 +100,7 @@ func (r *Report) WriteToWriter(writer io.Writer) error {
 		return err
 	}
 
-	return tmpl.Execute(writer, r.model)
+	return tmpl.Execute(writer, r)
 }
 
 // WriteToFile writes the generated report content to a file with

helper/report.tmpl

@@ -102,7 +102,7 @@
 
             {{ range .Date }}
             data.addRow([
-                new Date("{{ .Format "2006-01-02" }}"),
+                new Date("{{ .Format $.DateFormat }}"),
                 {{ range $.Columns }}
                 {{ .Value }},
                 {{ end }}
@@ -119,4 +119,4 @@
     </script>
 </body>
 
-</html>
+</html>

strategy/backtest.go

@@ -62,6 +62,9 @@ type Backtest struct {
 
 	// WriteStrategyReports indicates whether the individual strategy reports should be generated.
 	WriteStrategyReports bool
+
+	// DateFormat is the date format that is used in the reports.
+	DateFormat string
 }
 
 // backtestResult encapsulates the outcome of running a strategy.
@@ -95,6 +98,7 @@ func NewBacktest(repository asset.Repository, outputDir string) *Backtest {
 		Workers:              DefaultBacktestWorkers,
 		LastDays:             DefaultLastDays,
 		WriteStrategyReports: DefaultWriteStrategyReports,
+		DateFormat:           helper.DefaultReportDateFormat,
 	}
 }
 
@@ -204,6 +208,7 @@ func (b *Backtest) worker(names <-chan string, bestResults chan<- *backtestResul
 			// Generate inidividual strategy report.
 			if b.WriteStrategyReports {
 				report := st.Report(helper.SliceToChan(snapshotsSlice))
+				report.DateFormat = b.DateFormat
 
 				err := report.WriteToFile(path.Join(b.outputDir, b.strategyReportFileName(name, st.Name())))
 				if err != nil {