go-chart/value_formatter.go

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2016-07-10 10:11:47 +02:00
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
}