在JS中判断一个对象是否包含某个属性,可以使用in,hasOwnProperty()andpropertyIsEnumerable() or simply by querying the property. 或者直接使用查询属性。 in--It returnstrueif the object has an own property or an inherited property 用In,当前对象存在或者有继承,就返回true。 hasOwnProperty()--Totest wh...
}//AS也可以使用,不是undefined,而是null---if(testDemo.hasOwnProperty('name')){ ... } 差不多就这三种方式,如有更多请留言; 对了,如果是json串可以使用: varcheckData = "{'auth_token': 'xxxx','public_type': 'discharge_registration'}";varcheck = eval("(" + checkData + ")"); docume...
func JSObjectHasProperty( _ ctx: JSContextRef!, _ object: JSObjectRef!, _ propertyName: JSStringRef! ) -> Bool Parameters object The JSObjectRef to test. propertyName A JSStringRef that contains the property's name. Return Value true if the object has a property with a name that ma...
object The JSObjectRef to test. propertyKey A JSValueRef that contains the property key to use when looking up the property. exception A pointer to a JSValueRef to store an exception in, if any. Pass NULL to discard any exception. Return Value YES if the object has a property with ...
1、通过原始构造函数 new Object();创建一个对象,然后赋值; var testObj= new Object(); testObj.name = "shangguan"; testObj.age= 25; testObj.action = function () { return this.name; } 1. 2. 3. 4. 5. 6. 2、直接新建对象,不通过构造函数(而且直接新建速度比构造器还快一些!) ...
convert forEach to for...of -Object.keys(json).forEach((name) => { +for (const name of Object.keys(json)) { manage(name, json[name]); -}); +}convert for...in to for...of -for (const name in object) { - if (object.hasOwnProperty(name)) { +for (const name of ...
Once you have constructed a JSDOM object, it will have the following useful capabilities: Properties The property window retrieves the Window object that was created for you. The properties virtualConsole and cookieJar reflect the options you pass in, or the defaults created for you if nothing ...
n] === "object" ? JSON.stringify(t[n], function(t, e) { // 将数值转换为字符...
keys = object->GetCachedEnumKeysWithElements(); } } else { keys = object->GetEnumKeys(); } // For-In Body: for (size_t i = 0; i < keys->length(); i++) { // For-In Next: String* key = keys[i]; ...
Object.defineProperties(obj,props) 直接在一个对象上定义新的属性或修改现有属性,并返回该对象。 代码语言:javascript 复制 varobj={};Object.defineProperties(obj,{'property1':{value:true,writable:true},'property2':{value:'Hello',writable:false}// etc. etc.});console.log(obj)// {property1: tru...