Js does not work in some cases when passing values by reference type

give an example 


var a = function (ctx) {
    debugger // ctx {data: 555, name: 777}
    b(ctx);
    debugger; // ctx {data: 555, name: 777}
    return ctx;
}
var b = function (ctx) {
    ctx.age = 7;  //  
    ctx = ctx.data; //  ctx  555
    
    debugger; // ctx 555
}
let d = a({
    data: 555,
    name: 777
});
console.log(d); // {data: 555, name: 777, age: 777} ???  555

I"m a little confused. This is a value passed by reference type. The b function makes changes to the incoming object, and adding a age attribute works. But ctx = ctx.data; doesn"t work. I"m a little blinded.

OK, got it, because after ctx = ctx.data , I was disconnected from the original object

like 



var obj = {}
obj = 123;
The

reference has been disconnected, the b function does not change the ctx object, but the variable ctx in the b function points to, and the a function still points to the original function.

Javascript
May.04,2022 
var a = { name: 'a' };
var b = { name: 'b' };

var c = a; //c->a
c.name = 'a change to c';
c = b; //c->b
ctx in

b is a pointer to ctx in a . 

ctx.age = 7  // `ctx`
ctx = ctx.data  //

already knows the answer,
because after ctx = ctx.data, it is disconnected from the original object

like 

var obj = {}
obj = 123;
The

reference has been disconnected, the b function does not change the ctx object, but the variable ctx in the b function points to, and the a function still points to the original function.

Previous: The regular asterisk (*) of nginx location does not match the dot (.) The path file of

Next: The nesting problem of RxJava inverse observable

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b38482-2ae45.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b38482-2ae45.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?