refactor(errors): move typed key and value handling to a new file for better organization and maintainability

Author: m-mizutani

errors.go

@@ -9,26 +9,6 @@ import (
 	"log/slog"
 )
 
-// TypedKey represents a type-safe key for error values
-type TypedKey[T any] struct {
-	name string
-}
-
-// NewTypedKey creates a new typed key with the given name
-func NewTypedKey[T any](name string) TypedKey[T] {
-	return TypedKey[T]{name: name}
-}
-
-// String returns the string representation of the key for debugging
-func (k TypedKey[T]) String() string {
-	return k.name
-}
-
-// Name returns the name of the key
-func (k TypedKey[T]) Name() string {
-	return k.name
-}
-
 type Option func(*Error)
 
 // Value sets key and value to the error
@@ -52,18 +32,6 @@ func ID(id string) Option {
 	}
 }
 
-// TypedValue sets typed key and value to the error
-func TypedValue[T any](key TypedKey[T], value T) Option {
-	return func(err *Error) {
-		err.typedValues[key.name] = value
-	}
-}
-
-// TV is alias of TypedValue
-func TV[T any](key TypedKey[T], value T) Option {
-	return TypedValue(key, value)
-}
-
 // Tag sets tag to the error
 func Tag(t tag) Option {
 	return func(err *Error) {
@@ -114,15 +82,6 @@ func Values(err error) map[string]any {
 	return nil
 }
 
-// TypedValues returns map of key and value that is set by TypedValue. All wrapped goerr.Error typed key and values will be merged. Key and values of wrapped error is overwritten by upper goerr.Error.
-func TypedValues(err error) map[string]any {
-	if e := Unwrap(err); e != nil {
-		return e.TypedValues()
-	}
-
-	return nil
-}
-
 // Tags returns list of tags that is set by WithTags. All wrapped goerr.Error tags will be merged. Tags of wrapped error is overwritten by upper goerr.Error.
 func Tags(err error) []string {
 	if e := Unwrap(err); e != nil {
@@ -343,40 +302,6 @@ func (x *Error) TypedValues() map[string]any {
 	return typedValues
 }
 
-// GetTypedValue returns value associated with the typed key from the error. It searches through the error chain.
-func GetTypedValue[T any](err error, key TypedKey[T]) (T, bool) {
-	if e := Unwrap(err); e != nil {
-		return getTypedValueFromError(e, key)
-	}
-
-	var zero T
-	return zero, false
-}
-
-func getTypedValueFromError[T any](err *Error, key TypedKey[T]) (T, bool) {
-	// Search in current error's typed values
-	if value, ok := err.typedValues[key.name]; ok {
-		// Key found at this level. This is the definitive value.
-		// Check if the type matches.
-		if typedValue, ok := value.(T); ok {
-			return typedValue, true
-		}
-		// Type does not match. Do not search deeper for this key.
-		var zero T
-		return zero, false
-	}
-
-	// Key not found at this level. Search in wrapped errors recursively.
-	if cause := err.Unwrap(); cause != nil {
-		if wrappedErr := Unwrap(cause); wrappedErr != nil {
-			return getTypedValueFromError(wrappedErr, key)
-		}
-	}
-
-	var zero T
-	return zero, false
-}
-
 func (x *Error) mergedValues() values {
 	merged := make(values)
 

typed_values.go

@@ -0,0 +1,76 @@
+package goerr
+
+// TypedKey represents a type-safe key for error values
+type TypedKey[T any] struct {
+	name string
+}
+
+// NewTypedKey creates a new typed key with the given name
+func NewTypedKey[T any](name string) TypedKey[T] {
+	return TypedKey[T]{name: name}
+}
+
+// String returns the string representation of the key for debugging
+func (k TypedKey[T]) String() string {
+	return k.name
+}
+
+// Name returns the name of the key
+func (k TypedKey[T]) Name() string {
+	return k.name
+}
+
+// TypedValue sets typed key and value to the error
+func TypedValue[T any](key TypedKey[T], value T) Option {
+	return func(err *Error) {
+		err.typedValues[key.name] = value
+	}
+}
+
+// TV is alias of TypedValue
+func TV[T any](key TypedKey[T], value T) Option {
+	return TypedValue(key, value)
+}
+
+// TypedValues returns map of key and value that is set by TypedValue. All wrapped goerr.Error typed key and values will be merged. Key and values of wrapped error is overwritten by upper goerr.Error.
+func TypedValues(err error) map[string]any {
+	if e := Unwrap(err); e != nil {
+		return e.TypedValues()
+	}
+
+	return nil
+}
+
+// GetTypedValue returns value associated with the typed key from the error. It searches through the error chain.
+func GetTypedValue[T any](err error, key TypedKey[T]) (T, bool) {
+	if e := Unwrap(err); e != nil {
+		return getTypedValueFromError(e, key)
+	}
+
+	var zero T
+	return zero, false
+}
+
+func getTypedValueFromError[T any](err *Error, key TypedKey[T]) (T, bool) {
+	// Search in current error's typed values
+	if value, ok := err.typedValues[key.name]; ok {
+		// Key found at this level. This is the definitive value.
+		// Check if the type matches.
+		if typedValue, ok := value.(T); ok {
+			return typedValue, true
+		}
+		// Type does not match. Do not search deeper for this key.
+		var zero T
+		return zero, false
+	}
+
+	// Key not found at this level. Search in wrapped errors recursively.
+	if cause := err.Unwrap(); cause != nil {
+		if wrappedErr := Unwrap(cause); wrappedErr != nil {
+			return getTypedValueFromError(wrappedErr, key)
+		}
+	}
+
+	var zero T
+	return zero, false
+}