minor

x/jsonx/iso8601.go

@@ -135,6 +135,15 @@ func (t ISO8601) String() string {
 	return tt.Format(ISO8601Layout)
 }
 
+// ToSimpleDate converts the current ISO8601 "t" to SimpleDate in specific location.
+func (t ISO8601) ToSimpleDate(in *time.Location) SimpleDate {
+	if in == nil {
+		in = time.UTC
+	}
+
+	return SimpleDateFromTime(t.ToTime().In(in))
+}
+
 // Value returns the database value of time.Time.
 func (t ISO8601) Value() (driver.Value, error) {
 	return time.Time(t), nil

x/jsonx/simple_date.go

@@ -13,6 +13,13 @@ const SimpleDateLayout = "2006-01-02"
 // SimpleDate holds a json "year-month-day" time.
 type SimpleDate time.Time
 
+// SimpleDateFromTime accepts a "t" Time and returns
+// a SimpleDate. If format fails, it returns the zero value of time.Time.
+func SimpleDateFromTime(t time.Time) SimpleDate {
+	date, _ := ParseSimpleDate(t.Format(SimpleDateLayout))
+	return date
+}
+
 // ParseSimpleDate reads from "s" and returns the SimpleDate time.
 func ParseSimpleDate(s string) (SimpleDate, error) {
 	if s == "" || s == "null" {
@@ -70,6 +77,19 @@ func (t SimpleDate) IsZero() bool {
 	return t.ToTime().IsZero()
 }
 
+// After reports whether the time instant t is after u.
+func (t SimpleDate) After(d2 SimpleDate) bool {
+	t1, t2 := t.ToTime(), d2.ToTime()
+	return t1.Truncate(24 * time.Hour).After(t2.Truncate(24 * time.Hour))
+}
+
+// Before reports whether the time instant t is before u.
+func (t SimpleDate) Before(d2 SimpleDate) bool {
+	t1, t2 := t.ToTime(), d2.ToTime()
+	return t1.Truncate(24 * time.Hour).Before(t2.Truncate(24 * time.Hour))
+	// OR: compare year and year's day.
+}
+
 // ToTime returns the standard time type.
 func (t SimpleDate) ToTime() time.Time {
 	return time.Time(t)

x/jsonx/simple_date_test.go

@@ -0,0 +1,59 @@
+package jsonx
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+)
+
+func TestJSONSimpleDate(t *testing.T) {
+	data := `{"start": "2021-08-20", "end": "2021-12-01", "nothing": null, "empty": ""}`
+	v := struct {
+		Start   SimpleDate `json:"start"`
+		End     SimpleDate `json:"end"`
+		Nothing SimpleDate `json:"nothing"`
+		Empty   SimpleDate `json:"empty"`
+	}{}
+	err := json.Unmarshal([]byte(data), &v)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !v.Nothing.IsZero() {
+		t.Fatalf("expected 'nothing' to be zero but got: %v", v.Nothing)
+	}
+
+	if !v.Empty.IsZero() {
+		t.Fatalf("expected 'empty' to be zero but got: %v", v.Empty)
+	}
+
+	loc := time.UTC
+
+	if expected, got := time.Date(2021, time.August, 20, 0, 0, 0, 0, loc), v.Start.ToTime(); expected != got {
+		t.Fatalf("expected 'start' to be: %v but got: %v", expected, got)
+	}
+
+	if expected, got := time.Date(2021, time.December, 1, 0, 0, 0, 0, loc), v.End.ToTime(); expected != got {
+		t.Fatalf("expected 'start' to be: %v but got: %v", expected, got)
+	}
+}
+
+func TestSimpleDateAterBefore(t *testing.T) {
+	d1, d2 := SimpleDateFromTime(time.Now()), SimpleDateFromTime(time.Now().AddDate(0, 0, 1))
+
+	if d1.After(d2) {
+		t.Fatalf("[after] expected d1 to be before d2")
+	}
+
+	if !d1.Before(d2) {
+		t.Fatalf("[before] expected d1 to be before d2")
+	}
+
+	if d2.Before(d1) {
+		t.Fatalf("[after] expected d2 to be after d1")
+	}
+
+	if !d2.After(d1) {
+		t.Fatalf("[after] expected d2 to be after d1")
+	}
+}