Usage of JavaScript classes

Create a class for the constructor method as follows:
Copy codeThe Code is as follows:
Function className (prop_1, prop_2, prop_3 ){
This. prop1 = prop_1;
This. prop2 = prop_2;
This. prop3 = prop_3 ;}

With the above class, we can create an instance for the class:
Copy codeThe Code is as follows:
Var obj_1 = new className (v1, v2, v3)
Var obj_2 = new className (v1, v2, v3)

We can also add a method to the class, which is actually the Function in the Function.
Copy codeThe Code is as follows:
Function className (prop_1, prop_2, prop_3 ){
This. prop1 = prop_1;
This. prop2 = prop_2;
This. prop3 = prop_3;
This. func = function new_meth (property ){
// Coding here
}
}

Attribute access domain:

In JavaScript, the attributes of an object are global by default, that is, the object can be directly accessed inside and outside the object. In the above example, this. prop1, this. prop2, And this. prop3 are all global attributes.

How to define private attributes? Using var, in the following example, price becomes a private property!
Copy codeThe Code is as follows:
Function Car (listedPrice, color ){
Var price = listedPrice;
This. color = color;
This. honk = function (){
Console. log ("BEEP !! ");
};
}

If you want to access a private property, you can add a method to the object to return this private property. Because the method is in the object, you can access the private property of the object. You can access this private property by calling this method externally. However, this cannot be used in the method. As in the above example, to access the price, you can add the method to the object:
Copy codeThe Code is as follows:
This. getPrice = function (){
// Return price here!
Return price;
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Inheritance:

Use the following syntax to inherit:
Copy codeThe Code is as follows:
ElectricCar. prototype = new Car ();

Use instanceOf to check whether an object inherits. true or false is returned.
Copy codeThe Code is as follows:
MyElectricCar instanceof Car

Add Method to the inherited object:
Copy codeThe Code is as follows:
// Use the constructor to define a new object
Function ElectricCar (listedPrice ){
This. atomicity = 100;
Var price = listedPrice;
}

// Make the new object inherit the Car
ElectricCar. prototype = new Car ();

// Add a method for the new object
ElectricCar. prototype. refuel = function (numHours ){
This. atomicity = + 5 * numHours;
};

Override the value or method of the prototype object:
After we inherit the prototype object, we inherit the prototype value and method. However, sometimes our object values or methods may be different. At this time, we can rewrite the values and methods of the prototype object to change the content of the new object.
Copy codeThe Code is as follows:
Function Car (listedPrice ){
Var price = listedPrice;
This. speed = 0;
This. numWheels = 4;

This. getPrice = function (){
Return price;
};
}

Car. prototype. accelerate = function (){
This. speed + = 10;
};

Function ElectricCar (listedPrice ){
Var price = listedPrice;
This. atomicity = 100;
}
ElectricCar. prototype = new Car ();

// Override the accelerate Method
ElectricCar. prototype. accelerate = function (){
This. speed + = 20;
};
// Add the new method deceleratepoliciccar. prototype. decelerate = function (secondsStepped ){
This. speed-= 5 * secondsStepped;
};

MyElectricCar = new ElectricCar (500 );

Mypoliciccar. accelerate ();
Console. log ("myElectricCar has speed" + myElectricCar. speed );
MyElectricCar. decelerate (3 );
Console. log ("myElectricCar has speed" + myElectricCar. speed );