Xiaobian do not know how everyone’s May Day, anyway, for xiaobian, there are still some harvest, today xiaobian continue to update SOME new features of JS objects, looking forward to progress with you. You can also follow my wechat public number, snail full stack.

Object.values() : Get an array of values in an Object

const obj = {
    name:"lilei".web:"www.baidu.com".course:"math"
}
console.log(Object.values(obj)) // ["lilei","www.baidu.com","math"]
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Object.entries() : returns a two-digit array, each containing a key and a value

const obj = {
    name:"lilei".web:"www.baidu.com".course:"math"
}
console.log(Object.entries(obj))  // [["name","lilei"],["web","www.baidu.com"],["course","math"]]
console.log(Object.entries(["a"."b"."c"])) // [["0","a"],["1","b"],["2","c"]]
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Loop traversal: Combined with deconstruction and string templates in ES6

const obj = {
    name:"lilei".web:"www.baidu.com".course:"math"
}
for(let [key,val] of Object.entries(obj)){
    console.log(`${key}:${val}`)  // name:lilei web:www.baidu.com course:math
}
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4. Grammar before ES8

const obj = {
    name:"lilei".web:"www.baidu.com".course:"math"
}
console.log(Object.keys(obj)) // ["name","web","course"]
const res = Object.keys(obj).map(key= > obj[key])
console.log(res) // ["lilei","www.baidu.com","math"]
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Five, the Object. GetOwnPropertyDescriptors () : access to the Object itself attribute modifiers

const obj = {
    name:"lilei".course:"math"
}
const desc = Object.getOwnPropertyDescriptors(obj)
console.log(desc) 
/ / {
// name:{
// value:"lilei", // Default value
// writable:true, // whether the attribute can be changed
Enumerable :true; // Enumerable :true; In loop traversal
// Signals :true // Can be freely deleted by delete
/ /},
// course:{
// value:"math",
// writable:true,
// enumerable:true,
// configurable:true
/ /}
// }
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6. Combine with Reflect

const obj= {}
Reflect.defineProperty(obj,'name', {value:"lilei".writable:false.configurable:false.enumerable:true
})
Reflect.defineProperty(obj,'age', {value:18.writable:false.configurable:false.enumerable:false
})
console.log(obj) // {name:"lilei"}
obj.name= "zhangsan"
console.log(obj) // {name:"lilei"}
delete obj.name
console.log(obj) // {name:"lilei"}
for(let key in obj){
    console.log(key)  // Only name. There is no age
}
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Seven, Object. GetOwnPropertyDescriptor ()

const obj = {
    name:"lilei".course:"math"
}
const desc = Object.getOwnPropertyDescriptor(obj,"name")
console.log(desc)
/ / {
// value:"lilei", // Default value
// writable:true, // whether the attribute can be changed
Enumerable :true; // Enumerable :true; In loop traversal
// Signals :true // Can be freely deleted by delete
// }
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