When there is a time type in the object ( The time type will be changed to string data )
const obj = {
date: new Date()
}
console.log(typeof obj.date === 'object') //true
const objCopy = JSON.parse(JSON.stringify(obj));
console.log(obj.date.getTime()) // Normal use
console.log(typeof objCopy.date) // Output value string string
console.log(objCopy.date.getTime()) // Report errors objCopy.date.getTime is not a function
We will be surprised to find ,
getTime () It can't be adjusted ？？？( Is it a little strange )
getYearFull() It can't be adjusted .
The built-in methods for all time types cannot be adjusted .
but ,string The built-in method of type is fully adjusted .
Among objects undefined or function Type , They will lose it directly
const obj = {
undef: undefined,
fun: () => { console.log(' Creak , ABA, ABA ') }
}
console.log("obj",obj);
const objCopy = JSON.parse(JSON.stringify(obj));
console.log("objCopy",objCopy)
Then you will find out , Both types of data are gone .
The return is an empty object
When there is... In the object NaN、Infinity and -Infinity These three values , Will become null
1.7976931348623157E+10308 Is the maximum number of floating point numbers Is shown as Infinity
-1.7976931348623157E+10308 Is the minimum lower line of a floating point number Is shown as -Infinity
const obj = {
nan: NaN,
infinityMax: 1.7976931348623157E+10308,
infinityMin: -1.7976931348623157E+10308,
}
console.log("obj", obj);
const objCopy = JSON.parse(JSON.stringify(obj));
console.log("objCopy", objCopy)
When an object is referenced circularly -- Will report a mistake
const obj = {
objChild: null
}
obj.objChild = obj;
const objCopy = JSON.parse(JSON.stringify(obj));
console.log("objCopy", objCopy)
If you are lucky enough to need to copy such an object
const obj = {
nan:NaN,
infinityMax:1.7976931348623157E+10308,
infinityMin:-1.7976931348623157E+10308,
undef: undefined,
fun: () => { console.log(' Creak , ABA, ABA ') },
date:new Date,
}
Then you will find out , good heavens , None of them are normal .
Last
You're still using JSON.stringify() To implement deep copy ？
If you copy objects with new Date,undefined, function ,NaN,infinityMax, infinityMin.
this 6 When planting , You have to be careful , There will be problems
If still in use , Be careful .
Article from link ：https://juejin.cn/post/7113829141392130078
