02 js prototype chain

1 js prototype chain is not open around the topic. Directly on speak.

/ * * 
 * 1. JS in the prototype chain is kind of how? With different class prototype chain and without the class. 
 * / 

 Const util = the require ( 'util' );
  function A () { 
    console.info ( "the I AM A" ); 
 } 

 function B () { 
    console.info ( "the I AM B" ); 
} 
    
function C () { 
    console.info ( "the I AM C" ); 
} 

util.inherits (B, A); 
util.inherits (C, B); 
class {the CA 
    constructor () { 
        console.info ( "I AM the CA" ); 
    } 

    Doca () { 
        console.info ( "Doca"
}

class  CB extends CA{
    constructor(){
        super();
        console.info("i am CB");
    }

    doCB(){
        console.info(" do CB ");
    }
}

class  CC extends CB {
    constructor(){
        super();
        console.info("i am CC");
    }

    doCC(){
        console.info(" i am doCC");
    }
}

//原型链继承如下：
var c = new C();
console.info( c.__proto__ ===C.prototype); 
console.info (c .__ therefore __.__ proto__ === B.prototype); 
console.info (c .__ therefore __.__ therefore __.__ proto__ === A.prototype); 
console.info (c .__ therefore __.__ therefore __.__ therefore __.__ proto__ === Object.prototype); 
console.info (c .__ therefore __.__ therefore __.__ therefore __.__ therefore __.__ proto__ === null ); 

// class 
var cc = new CC (); 
console.info (cc .__ proto__ === CC.prototype); 
console.info (cc .__ therefore __.__ proto__ === CB.prototype); 
console.info (cc .__ therefore __.__ therefore __.__ proto__ === CA.prototype);
console.info (CC .__ proto __.__ proto __.__ proto __.__ proto__ === Object.prototype); 
console.info (CC .__ proto __.__ proto __.__ proto __.__ proto __.__ proto__ === null ); 

// The following is a class hierarchy . class and non-class are different 
console.info ( "Class Hierarchy" ); 
console.info (C.prototype.constructor === C); // prototypes of the configuration C = itself 
console.info (C .__ proto__ = the Function.prototype ==); // the __proto__ all classes of prototype points Function, i.e. the main configuration of the prototype. 
console.info (Function .__ proto__ === Function.prototype); //
 
console.info ( "class inheritance relationship with the class" ); 
console.info (CC .__ proto__ === CB); //CC __proto__ with the class point, cb, eventually most wanted Function prototype. 
console.info (CC .__ proto __.__ proto__ === CA); 
console.info (CA .__ proto__ === Function.prototype);

Prototype chain to keep in mind the following points:

1. Every thing has __proto__

2. Prototype prototype class = class. construct the prototype class = class.

3. Small c prototype prototype of the __proto__ = C, C of __proto __ = B and prototype prototype, the prototype __proto__ B = A prototype of the prototype A = __proto__ Object and Object of the prototype _ _proto__ = null; this is the prototype chain, it is very simple.

4. an inherited class, CC of __proto__ = CB, CB of __proto__ = CA, CA in __proto__ = Function prototypes.

Util.inherits when using inheritance, C, B, A, Function Function equal to the __proto__ prototype.

As long as all the above in mind, more practice, one can grasp the prototype chain.

If you have not read the above, you can refer to: https://blog.csdn.net/m0_37589327/article/details/78655038

02 js prototype chain

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