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

Last update on May 30 2022 10:02:53 (UTC/GMT +8 hours)

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:

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 insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = [];
arr[0] = "Jani";
arr[1] = "Hege";
arr[2] = "Stale";
arr[3] = "Kai Jim";
arr[4] = "Borge";

console.log(arr.join());
arr.splice(2, 0, "Lene");
console.log(arr.join());

Ref: https://bit.ly/2BXbp04