snapshot.

value_formatter.go

@@ -0,0 +1,43 @@
+package chart
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/blendlabs/go-util"
+)
+
+// ValueFormatter is a function that takes a value and produces a string.
+type ValueFormatter func(v interface{}) string
+
+// TimeValueFormatter is a ValueFormatter for timestamps.
+func TimeValueFormatter(v interface{}) string {
+	return TimeValueFormatterWithFormat(v, DefaultDateFormat)
+}
+
+// TimeValueFormatterWithFormat is a ValueFormatter for timestamps with a given format.
+func TimeValueFormatterWithFormat(v interface{}, dateFormat string) string {
+	if typed, isTyped := v.(time.Time); isTyped {
+		return typed.Format(dateFormat)
+	}
+	if typed, isTyped := v.(int64); isTyped {
+		return time.Unix(typed, 0).Format(dateFormat)
+	}
+	if typed, isTyped := v.(float64); isTyped {
+		return time.Unix(int64(typed), 0).Format(dateFormat)
+	}
+	return util.StringEmpty
+}
+
+// FloatValueFormatter is a ValueFormatter for float64.
+func FloatValueFormatter(v interface{}) string {
+	return FloatValueFormatterWithFormat(v, "%.2f")
+}
+
+// FloatValueFormatterWithFormat is a ValueFormatter for float64 with a given format.
+func FloatValueFormatterWithFormat(v interface{}, floatFormat string) string {
+	if typed, isTyped := v.(float64); isTyped {
+		return fmt.Sprintf(floatFormat, typed)
+	}
+	return util.StringEmpty
+}