What does instanceof mean?

Instanceof is an operator in JavaScript, used to detect whether the "prototype" attribute of the constructor appears anywhere in the prototype chain of the object. The syntax is "object instanceof constructor", where object is to be detected The object, constructor is the constructor to be checked.

# Operating system for this tutorial: Window10 system, Dell G3 computer.

instanceof is an operator in JavaScript that is used to detect whether the prototype attribute of a constructor appears anywhere in the object's prototype chain. It is used to determine whether an object is an instance of a class (constructor).

Specifically, the syntax of instanceof is: object instanceof constructor, where object is the object to be detected, and constructor is the constructor to be checked.

For example:

function Car(make, model, year) {
  this.make = make;
  this.model = model;
  this.year = year;
}

var myCar = new Car('Honda', 'Accord', 1998);
console.log(myCar instanceof Car); // true

In the above example, the result of myCar instanceof Car is true because myCar is an instance created through the Car constructor.

The instanceof operator is very useful for checking inheritance relationships and object types. It can help us determine whether an object belongs to a specific class or an instance of its parent class. However, it should be noted that the instanceof operator also has some limitations. For example, using instanceof for basic data types (such as strings, numbers, etc.) cannot obtain the expected results, so you need to pay attention to its scope of application when using it.

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