js not instanceof
if ( !(obj instanceof Array) ) {
console.log('obj is not an Array')
}js not instanceof
if ( !(obj instanceof Array) ) {
console.log('obj is not an Array')
}Explain about instanceof operator in java
An instanceof in Java is a comparison operator which, given an object instance,
checks whether that instance is of a specified type (class/sub-class/interface)
or not. Just like other comparison operators, it returns true or false.
Comparing any object instance with a null type through instanceof operator
returns a false.
Instanceof operator is used to test the object is of which type.
Syntax : <reference expression> instanceof <destination type>
Instanceof returns true if reference expression is subtype of destination type.
Instanceof returns false if reference expression is null.instanceof javascript
var color = "red";
var color2 = {};
color instanceof String // will return true
color2 instanceof Object // will return trueinsanceof
The instanceof operator tests to see if the prototype property of a constructor
appears anywhere in the prototype chain of an object. The return value is a
boolean value.
For example :-
function Car(make, model, year) {
this.make = make;
this.model = model;
this.year = year;
}
const auto = new Car('Honda', 'Accord', 1998);
console.log(auto instanceof Car);
// expected output: true
console.log(auto instanceof Object);
// expected output: truejs class check if new instance
new Date() instanceof Date; // => trueinstanceof
function Phone(serial, price, color){
this.serial = serial;
this.price = price;
this.color = color;
}
let phone1 = new Phone('abc1', 200, 'red');
let phone2 = new Phone('abc2', 400, 'green');
//instanceof
console.log(phone1 instanceof Phone) // true
//constructor
console.log(phone1.constructor === Phone) //trueCopyright © 2021 Codeinu
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