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object assign 用途

Posted on
  • 为对象添加属性
  • 为对象添加方法
  • 浅克隆
  • 合并多个对象
  • 属性指定默认值
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const DEFAULTS = {
	logLevel: 0,
	outputFormat: 'html'
};
function processContent(options) {
	let options = Object.assign({}, DEFAULTS, options);
}

Object.create()、new Object()和{}的区别

直接字面量创建

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var objA = {};
objA.name = 'a';
objA.sayName = function() {
    console.log(`My name is ${this.name} !`);
}
// var objA = {
//     name: 'a',
//     sayName: function() {
//         console.log(`My name is ${this.name} !`);
//     }
// }
objA.sayName();
console.log(objA.__proto__ === Object.prototype); // true
console.log(objA instanceof Object); // true

new关键字创建

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var objB = new Object();
// var objB = Object();
objB.name = 'b';
objB.sayName = function() {
    console.log(`My name is ${this.name} !`);
}
objB.sayName();
console.log(objB.__proto__ === Object.prototype); // true
console.log(objB instanceof Object); // true

Object.create 创建