chore: improve map cast functions

map.go

@@ -15,7 +15,7 @@ func toMapE[K comparable, V any](i any, keyFn func(any) K, valFn func(any) V) (m
 	m := map[K]V{}
 
 	if i == nil {
-		return m, fmt.Errorf("unable to cast %#v of type %T to %T", i, i, m)
+		return nil, fmt.Errorf(errorMsg, i, i, m)
 	}
 
 	switch v := i.(type) {
@@ -45,31 +45,34 @@ func toMapE[K comparable, V any](i any, keyFn func(any) K, valFn func(any) V) (m
 
 	case string:
 		err := jsonStringToObject(v, &m)
+		if err != nil {
+			return nil, err
+		}
 
-		return m, err
+		return m, nil
 
 	default:
-		return m, fmt.Errorf("unable to cast %#v of type %T to %T", i, i, m)
+		return nil, fmt.Errorf(errorMsg, i, i, m)
 	}
 }
 
 func toStringMapE[T any](i any, fn func(any) T) (map[string]T, error) {
 	return toMapE(i, ToString, fn)
 }
 
-// ToStringMapStringE casts an interface to a map[string]string type.
+// ToStringMapStringE casts any value to a map[string]string type.
 func ToStringMapStringE(i any) (map[string]string, error) {
 	return toStringMapE(i, ToString)
 }
 
-// ToStringMapStringSliceE casts an interface to a map[string][]string type.
-func ToStringMapStringSliceE(i interface{}) (map[string][]string, error) {
+// ToStringMapStringSliceE casts any value to a map[string][]string type.
+func ToStringMapStringSliceE(i any) (map[string][]string, error) {
 	m := map[string][]string{}
 
 	switch v := i.(type) {
 	case map[string][]string:
 		return v, nil
-	case map[string][]interface{}:
+	case map[string][]any:
 		for k, val := range v {
 			m[ToString(k)] = ToStringSlice(val)
 		}
@@ -78,10 +81,10 @@ func ToStringMapStringSliceE(i interface{}) (map[string][]string, error) {
 		for k, val := range v {
 			m[ToString(k)] = []string{val}
 		}
-	case map[string]interface{}:
+	case map[string]any:
 		for k, val := range v {
 			switch vt := val.(type) {
-			case []interface{}:
+			case []any:
 				m[ToString(k)] = ToStringSlice(vt)
 			case []string:
 				m[ToString(k)] = vt
@@ -90,49 +93,54 @@ func ToStringMapStringSliceE(i interface{}) (map[string][]string, error) {
 			}
 		}
 		return m, nil
-	case map[interface{}][]string:
+	case map[any][]string:
 		for k, val := range v {
 			m[ToString(k)] = ToStringSlice(val)
 		}
 		return m, nil
-	case map[interface{}]string:
+	case map[any]string:
 		for k, val := range v {
 			m[ToString(k)] = ToStringSlice(val)
 		}
 		return m, nil
-	case map[interface{}][]interface{}:
+	case map[any][]any:
 		for k, val := range v {
 			m[ToString(k)] = ToStringSlice(val)
 		}
 		return m, nil
-	case map[interface{}]interface{}:
+	case map[any]any:
 		for k, val := range v {
 			key, err := ToStringE(k)
 			if err != nil {
-				return m, fmt.Errorf("unable to cast %#v of type %T to map[string][]string", i, i)
+				return nil, fmt.Errorf(errorMsg, i, i, m)
 			}
 			value, err := ToStringSliceE(val)
 			if err != nil {
-				return m, fmt.Errorf("unable to cast %#v of type %T to map[string][]string", i, i)
+				return nil, fmt.Errorf(errorMsg, i, i, m)
 			}
 			m[key] = value
 		}
 	case string:
 		err := jsonStringToObject(v, &m)
-		return m, err
+		if err != nil {
+			return nil, err
+		}
+
+		return m, nil
 	default:
-		return m, fmt.Errorf("unable to cast %#v of type %T to map[string][]string", i, i)
+		return nil, fmt.Errorf(errorMsg, i, i, m)
 	}
+
 	return m, nil
 }
 
-// ToStringMapBoolE casts an interface to a map[string]bool type.
-func ToStringMapBoolE(i interface{}) (map[string]bool, error) {
+// ToStringMapBoolE casts any value to a map[string]bool type.
+func ToStringMapBoolE(i any) (map[string]bool, error) {
 	return toStringMapE(i, ToBool)
 }
 
-// ToStringMapE casts an interface to a map[string]interface{} type.
-func ToStringMapE(i interface{}) (map[string]interface{}, error) {
+// ToStringMapE casts any value to a map[string]any type.
+func ToStringMapE(i any) (map[string]any, error) {
 	fn := func(i any) any { return i }
 
 	return toStringMapE(i, fn)
@@ -142,7 +150,7 @@ func toStringMapIntE[T int | int64](i any, fn func(any) T, fnE func(any) (T, err
 	m := map[string]T{}
 
 	if i == nil {
-		return m, fmt.Errorf("unable to cast %#v of type %T to %T", i, i, m)
+		return nil, fmt.Errorf(errorMsg, i, i, m)
 	}
 
 	switch v := i.(type) {
@@ -172,12 +180,15 @@ func toStringMapIntE[T int | int64](i any, fn func(any) T, fnE func(any) (T, err
 
 	case string:
 		err := jsonStringToObject(v, &m)
+		if err != nil {
+			return nil, err
+		}
 
-		return m, err
+		return m, nil
 	}
 
 	if reflect.TypeOf(i).Kind() != reflect.Map {
-		return m, fmt.Errorf(errorMsg, i, i, m)
+		return nil, fmt.Errorf(errorMsg, i, i, m)
 	}
 
 	mVal := reflect.ValueOf(m)
@@ -195,19 +206,19 @@ func toStringMapIntE[T int | int64](i any, fn func(any) T, fnE func(any) (T, err
 	return m, nil
 }
 
-// ToStringMapIntE casts an interface to a map[string]int{} type.
+// ToStringMapIntE casts any value to a map[string]int type.
 func ToStringMapIntE(i any) (map[string]int, error) {
 	return toStringMapIntE(i, ToInt, ToIntE)
 }
 
-// ToStringMapInt64E casts an interface to a map[string]int64{} type.
-func ToStringMapInt64E(i interface{}) (map[string]int64, error) {
+// ToStringMapInt64E casts any value to a map[string]int64 type.
+func ToStringMapInt64E(i any) (map[string]int64, error) {
 	return toStringMapIntE(i, ToInt64, ToInt64E)
 }
 
 // jsonStringToObject attempts to unmarshall a string as JSON into
 // the object passed as pointer.
-func jsonStringToObject(s string, v interface{}) error {
+func jsonStringToObject(s string, v any) error {
 	data := []byte(s)
 	return json.Unmarshal(data, v)
 }