feat: add new method: MapOnExists - mapping data to the dst struct on…

…ly on key exists

README.md

@@ -41,6 +41,12 @@ Golang's application config manage tool library.
 
 ## Usage
 
+**Install**:
+
+```bash
+go get github.com/gookit/config/v2
+```
+
 Here using the yaml format as an example(`testdata/yml_other.yml`):
 
 ```yaml
@@ -126,6 +132,8 @@ Can use empty string for bind all config data to a struct:
 config.BindStruct("", &myConf)
 ```
 
+> `config.MapOnExists` like `BindStruct`，but map binding only if key exists
+
 ### Direct Read data
 
 - Get integer
@@ -292,7 +300,11 @@ type Options struct {
 - `Strings(key string) (arr []string)`
 - `StringMap(key string) (mp map[string]string)`
 - `Get(key string, findByPath ...bool) (value interface{})`
+
+**Mapping data to struct:**
+
 - `BindStruct(key string, dst interface{}) error`
+- `MapOnExists(key string, dst interface{}) error`
 
 ### Setting Values
 

README.zh-CN.md

@@ -40,6 +40,12 @@
 
 ## 快速使用
 
+**获取包**:
+
+```bash
+go get github.com/gookit/config/v2
+```
+
 这里使用yaml格式作为示例(`testdata/yml_other.yml`):
 
 ```yaml
@@ -126,6 +132,8 @@ config.WithOptions(func(opt *Options) {
 config.BindStruct("", &myConf)
 ```
 
+> `config.MapOnExists` 与 `BindStruct` 一样，但仅当 key 存在时才进行映射绑定
+
 ### 快速获取数据
 
 ```go
@@ -270,7 +278,11 @@ type Options struct {
 - `Strings(key string) (arr []string)`
 - `StringMap(key string) (mp map[string]string)`
 - `Get(key string, findByPath ...bool) (value interface{})`
+
+**将数据映射到结构体:**
+
 - `BindStruct(key string, dst interface{}) error`
+- `MapOnExists(key string, dst interface{}) error`
 
 ### 设置值
 

export.go

@@ -10,6 +10,7 @@ import (
 )
 
 // MapStruct alias method of the 'Structure'
+//
 // Usage:
 // 	dbInfo := &Db{}
 // 	config.MapStruct("db", dbInfo)
@@ -28,7 +29,23 @@ func (c *Config) BindStruct(key string, dst interface{}) error {
 	return c.Structure(key, dst)
 }
 
+// MapOnExists mapping data to the dst structure only on key exists.
+func MapOnExists(key string, dst interface{}) error {
+	return dc.MapOnExists(key, dst)
+}
+
+// MapOnExists mapping data to the dst structure only on key exists.
+func (c *Config) MapOnExists(key string, dst interface{}) error {
+	err := c.Structure(key, dst)
+	if err != nil && err == errNotFound {
+		return nil
+	}
+
+	return err
+}
+
 // Structure get config data and binding to the dst structure.
+//
 // Usage:
 // 	dbInfo := Db{}
 // 	config.Structure("db", &dbInfo)

export_test.go

@@ -98,7 +98,7 @@ func TestConfig_Structure(t *testing.T) {
 
 	some := struct {
 		Age  int
-		Kye  string
+		Key  string
 		Tags []int
 	}{}
 	err = BindStruct("sec", &some)
@@ -228,3 +228,26 @@ func TestMapStruct_embedded_struct_squash_true(t *testing.T) {
 	dump.Println(cfg1)
 	assert.Equal(t, 34, cfg1.Test1.B)
 }
+
+func TestMapOnExists(t *testing.T) {
+	cfg := Default()
+	cfg.ClearAll()
+
+	err := cfg.LoadStrings(JSON, `{
+"age": 28,
+"name": "inhere",
+"sports": ["pingPong", "跑步"]
+}`)
+	assert.NoError(t, err)
+	assert.NoError(t, MapOnExists("not-exists", nil))
+
+	user := &struct {
+		Age    int
+		Name   string
+		Sports []string
+	}{}
+	assert.NoError(t, MapOnExists("", user))
+
+	assert.Equal(t, 28, user.Age)
+	assert.Equal(t, "inhere", user.Name)
+}