feat: add support for camelCase JSON keys

resolver.go

@@ -29,7 +29,7 @@ func (r ResolverFunc) Validate(app *Application) error { return nil } // nolint:
 
 // JSON returns a Resolver that retrieves values from a JSON source.
 //
-// Hyphens in flag names are replaced with underscores.
+// Flag names are used as JSON keys indirectly, by tring snake_case and camelCase variants.
 func JSON(r io.Reader) (Resolver, error) {
 	values := map[string]interface{}{}
 	err := json.NewDecoder(r).Decode(&values)
@@ -38,9 +38,12 @@ func JSON(r io.Reader) (Resolver, error) {
 	}
 	var f ResolverFunc = func(context *Context, parent *Path, flag *Flag) (interface{}, error) {
 		name := strings.ReplaceAll(flag.Name, "-", "_")
+		snakeCaseName := snakeCase(flag.Name)
 		raw, ok := values[name]
 		if ok {
 			return raw, nil
+		} else if raw, ok = values[snakeCaseName]; ok {
+			return raw, nil
 		}
 		raw = values
 		for _, part := range strings.Split(name, ".") {
@@ -58,3 +61,8 @@ func JSON(r io.Reader) (Resolver, error) {
 
 	return f, nil
 }
+
+func snakeCase(name string) string {
+	name = strings.Join(strings.Split(strings.Title(name), "-"), "") //nolint: staticcheck
+	return strings.ToLower(name[:1]) + name[1:]
+}

resolver_test.go

@@ -206,7 +206,7 @@ func TestJSONBasic(t *testing.T) {
 		"string": "🍕",
 		"slice": [5, 8],
 		"bool": true,
-		"slice_with_commas": ["a,b", "c"],
+		"sliceWithCommas": ["a,b", "c"],
 		"one":{
 			"string": "one value"
 		},