refactor: use pointer to collection

handler.go

@@ -21,7 +21,6 @@ func HandleBase(w http.ResponseWriter, r *http.Request, s *Source, opt *ServeOpt
 
 	path := r.URL.Path[1:]
 	response := s.data[path]
-	collection := response.([]interface{})
 
 	if response == nil {
 		w.WriteHeader(http.StatusNotFound)
@@ -32,24 +31,23 @@ func HandleBase(w http.ResponseWriter, r *http.Request, s *Source, opt *ServeOpt
 	case http.MethodGet:
 		data := GetAll(
 			r.URL.Query(),
-			collection,
+			response,
 		)
 
 		json.NewEncoder(w).Encode(data)
 	case http.MethodPost:
 		Create(
 			r.Body,
-			&collection,
+			response,
 		)
 
 		w.WriteHeader(http.StatusCreated)
-		json.NewEncoder(w).Encode(r.Body)
 	case http.MethodDelete:
 		id := r.URL.Path[strings.LastIndex(r.URL.Path, "/")+1:]
 
 		Delete(
 			id,
-			&collection,
+			response,
 		)
 
 		w.WriteHeader(http.StatusNoContent)

main.go

@@ -12,7 +12,7 @@ import (
 )
 
 type Source struct {
-	data map[string]interface{}
+	data map[string]*[]interface{}
 }
 
 type ServeOptions struct {
@@ -30,7 +30,7 @@ func read(path string) *Source {
 
 	defer file.Close()
 
-	jsonMap := make(map[string]interface{})
+	jsonMap := make(map[string]*[]interface{})
 
 	if err = json.NewDecoder(file).Decode(&jsonMap); err != nil {
 		log.Fatal(err)

repository.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"encoding/json"
-	"fmt"
 	"io"
 	"net/url"
 	"strconv"
@@ -11,14 +10,14 @@ import (
 
 func GetAll(
 	params url.Values,
-	collection []interface{},
+	collection *[]interface{},
 ) []interface{} {
 	result := []interface{}{}
 	limit, _ := strconv.Atoi(params.Get("_limit"))
 
 	if len(params) > 0 {
 		count := 0
-		for _, item := range collection {
+		for _, item := range *collection {
 			hasLimitReached := limit > 0 && count >= limit
 
 			if hasLimitReached {
@@ -56,7 +55,7 @@ func GetAll(
 			count += 1
 		}
 	} else {
-		result = collection
+		result = *collection
 	}
 
 	return result
@@ -68,18 +67,10 @@ func Create(
 ) error {
 	var body map[string]interface{}
 
-	err := json.NewDecoder(payload).Decode(&body)
-	if err != nil {
+	if err := json.NewDecoder(payload).Decode(&body); err != nil {
 		return err
 	}
 
-	for _, item := range *collection {
-		item := item.(map[string]interface{})
-		if item["id"] == body["id"] {
-			return fmt.Errorf("id already exists")
-		}
-	}
-
 	*collection = append(*collection, body)
 
 	return nil