JavaScript抽象
抽象是一种隐藏实现细节并仅向用户显示功能的方法。换句话说，它忽略了无关的细节，只显示了所需的细节。
要记住的要点
我们无法创建Abstract Class的实例。
它减少了代码的重复。
JavaScript抽象示例
示例1
让我们检查是否可以创建Abstract类的实例。
<script>
//Creating a constructor function
function Vehicle()
{
this.vehicleName= vehicleName;
throw new Error("You cannot create an instance of Abstract class");
}
Vehicle.prototype.display=function()
{
return this.vehicleName;
}
var vehicle=new Vehicle();
</script>
示例2
让我们看一个实现抽象的例子。
<script>
//Creating a constructor function
function Vehicle()
{
this.vehicleName="vehicleName";
throw new Error("You cannot create an instance of Abstract Class");
}
Vehicle.prototype.display=function()
{
return "Vehicle is: "+this.vehicleName;
}
//Creating a constructor function
function Bike(vehicleName)
{
this.vehicleName=vehicleName;
}
//Creating object without using the function constructor
Bike.prototype=Object.create(Vehicle.prototype);
var bike=new Bike("Honda");
document.writeln(bike.display());
</script>
输出：
Vehicle is: Honda
示例3
在此示例中，我们使用instanceof运算符测试对象是否引用了相应的类。
<script>
//Creating a constructor function
function Vehicle()
{
this.vehicleName=vehicleName;
throw new Error("You cannot create an instance of Abstract class");
}
//Creating a constructor function
function Bike(vehicleName)
{
this.vehicleName=vehicleName;
}
Bike.prototype=Object.create(Vehicle.prototype);
var bike=new Bike("Honda");
document.writeln(bike instanceof Vehicle);
document.writeln(bike instanceof Bike);
</script>
输出：
true true
