feat(ToStringMapStringE): Add support for non string JOSN value

cast_test.go

@@ -907,6 +907,8 @@ func TestToStringMapStringE(t *testing.T) {
 	var jsonString = `{"key 1": "value 1", "key 2": "value 2", "key 3": "value 3"}`
 	var invalidJsonString = `{"key 1": "value 1", "key 2": "value 2", "key 3": "value 3"`
 	var emptyString = ""
+	var jsonStringWithNonString = `{"key 1": "100", "key 2": -200, "key 3": 3.1415926}`
+	var mapStringWithNonString = map[string]string{"key 1": "100", "key 2": "-200", "key 3": "3.1415926"}
 
 	tests := []struct {
 		input  interface{}
@@ -918,6 +920,7 @@ func TestToStringMapStringE(t *testing.T) {
 		{interfaceMapString, stringMapString, false},
 		{interfaceMapInterface, stringMapString, false},
 		{jsonString, stringMapString, false},
+		{jsonStringWithNonString, mapStringWithNonString, false},
 
 		// errors
 		{nil, nil, true},

caste.go

@@ -874,8 +874,11 @@ func ToStringMapStringE(i interface{}) (map[string]string, error) {
 		}
 		return m, nil
 	case string:
-		err := jsonStringToObject(v, &m)
+		var temp = map[string]interface{}{}
-		return m, err
+		if err := jsonStringToObject(v, &temp); err != nil {
+			return nil, err
+		}
+		return ToStringMapStringE(temp)
 	default:
 		return m, fmt.Errorf("unable to cast %#v of type %T to map[string]string", i, i)
 	}

go.mod

@@ -1,5 +1,7 @@
 module github.com/spf13/cast
 
+go 1.15
+
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect