feat: support json marshal/unmarshal ksuid

.gitignore

@@ -29,3 +29,6 @@ _testmain.go
 
 # govendor
 /vendor/*/
+
+# ide
+.idea

ksuid.go

@@ -5,6 +5,7 @@ import (
 	"crypto/rand"
 	"database/sql/driver"
 	"encoding/binary"
+	"encoding/json"
 	"fmt"
 	"io"
 	"math"
@@ -38,8 +39,9 @@ const (
 )
 
 // KSUIDs are 20 bytes:
-//  00-03 byte: uint32 BE UTC timestamp with custom epoch
-//  04-19 byte: random "payload"
+//
+//	00-03 byte: uint32 BE UTC timestamp with custom epoch
+//	04-19 byte: random "payload"
 type KSUID [byteLength]byte
 
 var (
@@ -102,6 +104,11 @@ func (i KSUID) Get() interface{} {
 	return i
 }
 
+// Equal compares two KSUIDs for equality. It returns true if the two KSUIDs
+func (i KSUID) Equal(k2 KSUID) bool {
+	return bytes.Equal(i[:], k2[:])
+}
+
 // Set satisfies the flag.Value interface, making it possible to use KSUIDs as
 // part of of the command line options of a program.
 func (i *KSUID) Set(s string) error {
@@ -116,6 +123,10 @@ func (i KSUID) MarshalBinary() ([]byte, error) {
 	return i.Bytes(), nil
 }
 
+func (i KSUID) MarshalJSON() ([]byte, error) {
+	return json.Marshal(i.String())
+}
+
 func (i *KSUID) UnmarshalText(b []byte) error {
 	id, err := Parse(string(b))
 	if err != nil {
@@ -134,6 +145,21 @@ func (i *KSUID) UnmarshalBinary(b []byte) error {
 	return nil
 }
 
+func (i *KSUID) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return err
+	}
+
+	id, err := Parse(s)
+	if err != nil {
+		return fmt.Errorf("invalid KSUID: %w", err)
+	}
+
+	*i = id
+	return nil
+}
+
 // Value converts the KSUID into a SQL driver value which can be used to
 // directly use the KSUID as parameter to a SQL query.
 func (i KSUID) Value() (driver.Value, error) {

ksuid_test.go

@@ -2,7 +2,6 @@ package ksuid
 
 import (
 	"bytes"
-	"encoding/json"
 	"flag"
 	"fmt"
 	"sort"
@@ -122,6 +121,20 @@ func TestEncodeAndDecode(t *testing.T) {
 	}
 }
 
+func TestEqual(t *testing.T) {
+	x := New()
+	y := x
+
+	if !x.Equal(y) {
+		t.Error(x, "!=", y)
+	}
+
+	z := New()
+	if x.Equal(z) {
+		t.Error(x, "==", z)
+	}
+}
+
 func TestMarshalText(t *testing.T) {
 	var id1 = New()
 	var id2 KSUID
@@ -164,12 +177,13 @@ func TestMashalJSON(t *testing.T) {
 	var id1 = New()
 	var id2 KSUID
 
-	if b, err := json.Marshal(id1); err != nil {
-		t.Fatal(err)
-	} else if err := json.Unmarshal(b, &id2); err != nil {
-		t.Fatal(err)
-	} else if id1 != id2 {
-		t.Error(id1, "!=", id2)
+	b, err := id1.MarshalJSON()
+	if err != nil {
+		t.Error("unexpected error on marshal:", err)
+	}
+
+	if err := id2.UnmarshalJSON(b); err != nil {
+		t.Error("failed to unmarshal JSON:", err)
 	}
 }
 
@@ -309,7 +323,7 @@ func TestGetTimestamp(t *testing.T) {
 	x, _ := NewRandomWithTime(nowTime)
 	xTime := int64(x.Timestamp())
 	unix := nowTime.Unix()
-	if xTime != unix - epochStamp {
+	if xTime != unix-epochStamp {
 		t.Fatal(xTime, "!=", unix)
 	}
 }