Introduction to inheritance encapsulation in JavaScript_Basic knowledge

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/**
* When this function is called, only the first parameter is passed in. If the second one does not exist, the class is created
* When this function is called, two parameters are passed in, the first one The parameter is the base class, and the second parameter adds content based on the base class
*/
function extend(obj ,prop){
function F(){

}
//If the first parameter is of object type (i.e. json object), assign the key value of json to the F function Prototype F.prototype.key = value
if (typeof(obj) == "object") {
for(var name in obj){
F.prototype[name] = obj[name];
}
} else {//If the first parameter is of function type, assign the prototype of the secondary function to the F function. Prop must be passed by value (json object), so assign prop to F Prototype of function
F.prototype = obj.prototype;
for(var name in prop){
F.prototype[name] = prop[name];
}
}
return F;
}
//Because there is only one parameter here, the key and value of the json object will be assigned to the prototype of the F function in the extend function, and then the person variable will be used to receive the F function. This When person also becomes a function, this function also has the prototype name and sex of the F function
var person = extend({
name: "xxc",
sex: "man"
} );
//Pass the person function in. After entering the extend function, first assign the person prototype to the F function, and then assign the second parameter hope: "more money" to the F function. At this time, the F function The prototype has three things name, sex, hope
//Finally, the F function is returned, causing the prototype of person to be the same as the F function, with name, sex, hope
var person = extend(person,{
hope:"more money"
});
alert(person.prototype.name);//xxc
alert(person.prototype.sex);//man
alert(person.prototype .hope);//more money

Copy code The code is as follows:

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