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JavaScript: Delete a property from an object and print before or after deleting

JavaScript Object: Exercise-2 with Solution

Write a JavaScript program to delete the rollno property from the following object. Also print the object before or after deleting the property.
Sample object:
var student = {
name : "David Rayy",
sclass : "VI",
rollno : 12 };

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Delete a property from an object</title>
</head>
<body>
</body>
</html>

JavaScript Code:

var student =  { 
  name : "David Rayy", 
  sclass : "VI", 
  rollno : 12  };
console.log(student);
delete student.rollno;
console.log(student);

Sample Output:

{"name":"David Rayy","sclass":"VI","rollno":12}
{"name":"David Rayy","sclass":"VI"}

Flowchart:

Flowchart: JavaScript - Delete a property from an object and print before or after deleting.

Live Demo:

See the Pen javascript-object-exercise-2 by w3resource (@w3resource) on CodePen.


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JavaScript: Tips of the Day

How to check whether a string contains a substring in JavaScript?

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";

console.log(string.includes(substring));

includes doesn't have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found:

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Ref: https://bit.ly/3fFFgZv