The direction of constructor in js inheritance

problem description

js says that all instances inherit from the Object class by default.
but why does the constructor property of an instance of a custom constructor point not to Object, but to the constructor that constructed it?

the environmental background of the problems and what methods you have tried

related codes

/ / Please paste the code text below (do not replace the code with pictures)

what result do you expect? What is the error message actually seen?

Jun.06,2021

eventually inherits from Object and is not the default. Take a good look at the prototype chain!

    class A {
    }    
    
    let a = new A()
    
    function proto (instance) {
      if (!instance) return
      console.log('=============', instance.__proto__.constructor);
      proto(instance.__proto__)
    }

    proto(a)
    
    /*
        a
        
        A
        
        Object
    */ 
    
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-64f5-1e590f9-44235.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1e590f9-44235.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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