new /x/jsonx and /x/mathx util sub-packages

x/jsonx/duration.go

@@ -0,0 +1,54 @@
+package jsonx
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"errors"
+	"math"
+	"time"
+)
+
+// Duration is a JSON representation of the standard Duration type, until Go version 2 supports it under the hoods.
+type Duration time.Duration
+
+func (d Duration) MarshalJSON() ([]byte, error) {
+	return json.Marshal(time.Duration(d).String())
+}
+
+func (d *Duration) UnmarshalJSON(b []byte) error {
+	var v interface{}
+	if err := json.Unmarshal(b, &v); err != nil {
+		return err
+	}
+	switch value := v.(type) {
+	case float64:
+		*d = Duration(value)
+		return nil
+	case string:
+		v, err := time.ParseDuration(value)
+		if err != nil {
+			return err
+		}
+		*d = Duration(v)
+		return nil
+	default:
+		return errors.New("invalid duration")
+	}
+}
+
+func (d Duration) ToDuration() time.Duration {
+	return time.Duration(d)
+}
+
+func (d Duration) Value() (driver.Value, error) {
+	return int64(d), nil
+}
+
+// Set sets the value of duration in nanoseconds.
+func (d *Duration) Set(v float64) {
+	if math.IsNaN(v) {
+		return
+	}
+
+	*d = Duration(v)
+}