Use anonymous structs in UnmarshalJSON implementations

Signed-off-by: Vartan Benohanian <vartanbeno@gmail.com>

multi.go

@@ -51,19 +51,18 @@ type SubredditNames []string
 
 // UnmarshalJSON implements the json.Unmarshaler interface.
 func (n *SubredditNames) UnmarshalJSON(data []byte) error {
-	var subreddits []map[string]string
+	type subreddit struct {
+		Name string `json:"name"`
+	}
+	var subreddits []subreddit
 
 	err := json.Unmarshal(data, &subreddits)
 	if err != nil {
 		return err
 	}
 
-	for _, subreddit := range subreddits {
+	for _, sr := range subreddits {
-		name, ok := subreddit["name"]
+		*n = append(*n, sr.Name)
-		if !ok {
-			continue
-		}
-		*n = append(*n, name)
 	}
 
 	return nil
@@ -71,12 +70,13 @@ func (n *SubredditNames) UnmarshalJSON(data []byte) error {
 
 // MarshalJSON implements the json.Marshaler interface.
 func (n *SubredditNames) MarshalJSON() ([]byte, error) {
-	var subreddits []map[string]string
+	type subreddit struct {
+		Name string `json:"name"`
+	}
+	var subreddits []subreddit
 
-	for _, sr := range *n {
+	for _, name := range *n {
-		subreddits = append(subreddits, map[string]string{
+		subreddits = append(subreddits, subreddit{name})
-			"name": sr,
-		})
 	}
 
 	return json.Marshal(subreddits)
@@ -195,7 +195,7 @@ func (s *MultiService) Of(ctx context.Context, username string) ([]Multi, *Respo
 // Copy copies a multireddit.
 func (s *MultiService) Copy(ctx context.Context, copyRequest *MultiCopyRequest) (*Multi, *Response, error) {
 	if copyRequest == nil {
-		return nil, nil, errors.New("copyRequest cannot be nil")
+		return nil, nil, errors.New("copyRequest: cannot be nil")
 	}
 
 	path := "api/multi/copy"
@@ -217,7 +217,7 @@ func (s *MultiService) Copy(ctx context.Context, copyRequest *MultiCopyRequest)
 // Create creates a multireddit.
 func (s *MultiService) Create(ctx context.Context, createRequest *MultiCreateOrUpdateRequest) (*Multi, *Response, error) {
 	if createRequest == nil {
-		return nil, nil, errors.New("createRequest cannot be nil")
+		return nil, nil, errors.New("createRequest: cannot be nil")
 	}
 
 	path := "api/multi"
@@ -240,7 +240,7 @@ func (s *MultiService) Create(ctx context.Context, createRequest *MultiCreateOrU
 // If the multireddit does not exist, it will be created.
 func (s *MultiService) Update(ctx context.Context, multiPath string, updateRequest *MultiCreateOrUpdateRequest) (*Multi, *Response, error) {
 	if updateRequest == nil {
-		return nil, nil, errors.New("updateRequest cannot be nil")
+		return nil, nil, errors.New("updateRequest: cannot be nil")
 	}
 
 	path := fmt.Sprintf("api/multi/%s", multiPath)

post_test.go

@@ -17,7 +17,7 @@ var expectedPostAndComments = &PostAndComments{
 		Created: &Timestamp{time.Date(2020, 7, 18, 10, 26, 7, 0, time.UTC)},
 		Edited:  &Timestamp{time.Date(1, 1, 1, 0, 0, 0, 0, time.UTC)},
 
-		Permalink: Permalink("https://www.reddit.com/r/test/comments/testpost/test/"),
+		Permalink: "https://www.reddit.com/r/test/comments/testpost/test/",
 		URL:       "https://www.reddit.com/r/test/comments/testpost/test/",
 
 		Title: "Test",
@@ -44,7 +44,7 @@ var expectedPostAndComments = &PostAndComments{
 			Edited:  &Timestamp{time.Date(1, 1, 1, 0, 0, 0, 0, time.UTC)},
 
 			ParentID:  "t3_testpost",
-			Permalink: Permalink("https://www.reddit.com/r/test/comments/testpost/test/testc1/"),
+			Permalink: "https://www.reddit.com/r/test/comments/testpost/test/testc1/",
 
 			Body:     "Hi",
 			Author:   "testuser",
@@ -71,7 +71,7 @@ var expectedPostAndComments = &PostAndComments{
 						Edited:  &Timestamp{time.Date(1, 1, 1, 0, 0, 0, 0, time.UTC)},
 
 						ParentID:  "t1_testc1",
-						Permalink: Permalink("https://www.reddit.com/r/test/comments/testpost/test/testc2/"),
+						Permalink: "https://www.reddit.com/r/test/comments/testpost/test/testc2/",
 
 						Body:     "Hello",
 						Author:   "testuser",

things.go

@@ -32,7 +32,8 @@ func (p *Permalink) UnmarshalJSON(data []byte) error {
 	if err != nil {
 		return err
 	}
-	*p = Permalink("https://www.reddit.com" + v)
+	v = "https://www.reddit.com" + v
+	*p = Permalink(v)
 	return nil
 }
 
@@ -89,16 +90,20 @@ func (t *Things) init() {
 func (t *Things) UnmarshalJSON(b []byte) error {
 	t.init()
 
-	var children []map[string]interface{}
+	type thing struct {
-	if err := json.Unmarshal(b, &children); err != nil {
+		Kind string      `json:"kind"`
+		Data interface{} `json:"data"`
+	}
+
+	var things []thing
+	if err := json.Unmarshal(b, &things); err != nil {
 		return err
 	}
 
-	for _, child := range children {
+	for _, thing := range things {
-		data := child["data"]
+		byteValue, _ := json.Marshal(thing.Data)
-		byteValue, _ := json.Marshal(data)
 
-		switch child["kind"] {
+		switch thing.Kind {
 		case kindComment:
 			v := new(Comment)
 			if err := json.Unmarshal(byteValue, v); err == nil {