To get all own properties of an object in JavaScript, you can use theObject.getOwnPropertyNames()method. This method returns an array containing all the names of the enumerable and non-enumerableown propertiesfound directly on the object passed in as an argument. TheObject.getOwnPropertyNames()metho...
Object.keys/values/entries methods have similarity with for..in loop. They all ignore properties that apply Symbol(...) as a key. When you need symbols, you can use a separate method Object.getOwnPropertySymbols which returns an array consisting of only symbolic keys....
varbook={};Object.defineProperties(book,{_year:{writable:true,value:2004},edition:{writable:true,value:1},year:{get:function(){returnthis._year;},set:function(newValue){if(newValue>this._year){this.edition+=newValue-this._year;}this._year=newValue;}}});varattribute=Object...
🔸通过 Object.getOwnPropertyDescriptor(obj,propertyName) 方法可以获取一个属性的完整自有属性信息,返回的是一个“属性描述符”Descriptor对象。Descriptor主要结构如下,Object.create(proto, propertiesObject)的第二个参数也是用的这个结构来描述属性。 letdescriptor = { enumerable:false,//是否支持枚举 configurable:...
This example gets all properties of an object:Example // Create an Object const person = { firstName: "John", lastName : "Doe", language : "EN" }; // Get all Properties Object.getOwnPropertyNames(person); Try it Yourself » Object.getOwnPropertyNames() will also list properties ...
varobj =Object.create(null); obj.valueOf() // TypeError: Object [object Object] has no method 'valueOf' 上面代码中,对象obj的原型是null,它就不具备一些定义在Object.prototype对象上面的属性,比如valueOf方法。 使用Object.create方法...
Accessing JavaScript Properties The syntax for accessing the property of an object is: //objectName.property letage = person.age; or //objectName["property"] letage = person["age"]; or //objectName[expression] letage = person[x]; ...
Object.defineProperty() / Object.defineProperties() 新增/修改属性 obj prop / props 属性描述符 configurable 可改可删 默认false enumerable 可枚举属性 默认false value writable get set Object.getOwnPropertyDescriptor(obj, prop) 获取属性描述符对象 ...
#get some properties using reduce method #using es6 destructuring assignment #Underscore pick method Learn How to create a subset of a javascript object with examples. Let’s have a javascript object letuser={id:11,name:"frank",salary:5000,active:true,roles: ["admin","hr"],}; ...
Object.defineProperty(obj,propertyKey,propertyDescriptor):通过attributes对象,定义某个属性。 Object.defineProperties():通过attributes对象,定义多个属性。 Object.getOwnPropertyNames():返回直接定义在某个对象上面的全部属性的名称。//数组格式,Object.getOwnPropertyNames("abc") //["0", "1", "2", "length"] ...