JavaScript Object - Exercises, Practice, Solution

JavaScript Object [18 exercises with solution]

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1. Write a JavaScript program to list the properties of a JavaScript object.
Sample object:
var student = {
name : "David Rayy",
sclass : "VI",
rollno : 12 };
Sample Output: name,sclass,rollno
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2. 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 };
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3. Write a JavaScript program to get the length of a JavaScript object.
Sample object :
var student = {
name : "David Rayy",
sclass : "VI",
rollno : 12 };
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4. Write a JavaScript program to display the reading status (i.e. display book name, author name and reading status) of the following books.

var library = [ 
   {
       author: 'Bill Gates',
       title: 'The Road Ahead',
       readingStatus: true
   },
   {
       author: 'Steve Jobs',
       title: 'Walter Isaacson',
       readingStatus: true
   },
   {
       author: 'Suzanne Collins',
       title:  'Mockingjay: The Final Book of The Hunger Games', 
       readingStatus: false
   }];

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5. Write a JavaScript program to get the volume of a cylindrical with four decimal places using object classes.
Volume of a cylinder : V = πr²h
where r is the radius and h is the height of the cylinder.
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6. Write a bubble sort algorithm in JavaScript.
Note : Bubble sort is a simple sorting algorithm that works by repeatedly stepping through the list to be sorted,
Sample Data: [6,4,0, 3,-2,1]
Expected Output : [-2, 0, 1, 3, 4, 6]
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7. Write a JavaScript program that returns a subset of a string.
Sample Data: dog
Expected Output: ["d", "do", "dog", "o", "og", "g"]
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8. Write a JavaScript program to create a clock.
Note: The output will come every second.
Expected Console Output :
"14:37:42"
"14:37:43"
"14:37:44"
"14:37:45"
"14:37:46"
"14:37:47"
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9. Write a JavaScript program to calculate circle area and perimeter.
Note : Create two methods to calculate the area and perimeter. The radius of the circle will be supplied by the user.
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10. Write a JavaScript program to sort an array of JavaScript objects.
Sample Object :

var library = [ 
   {
       title:  'The Road Ahead',
       author: 'Bill Gates',
       libraryID: 1254
   },
   {
       title: 'Walter Isaacson',
       author: 'Steve Jobs',
       libraryID: 4264
   },
   {
       title: 'Mockingjay: The Final Book of The Hunger Games',
       author: 'Suzanne Collins',
       libraryID: 3245
   }];

Expected Output:

[[object Object] {
  author: "Walter Isaacson",
  libraryID: 4264,
  title: "Steve Jobs"
}, [object Object] {
  author: "Suzanne Collins",
  libraryID: 3245,
  title: "Mockingjay: The Final Book of The Hunger Games"
}, [object Object] {
  author: "The Road Ahead",
  libraryID: 1254,
  title: "Bill Gates"
}]

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11. Write a JavaScript function to print all the methods in a JavaScript object.
Test Data :
console.log(all_properties(Array));
["length", "name", "arguments", "caller", "prototype", "isArray", "observe", "unobserve"]
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12. Write a JavaScript function to parse an URL.
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13. Write a JavaScript function to retrieve all the names of an object's own and inherited properties.
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14. Write a JavaScript function to retrieve all the values of an object's properties.
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15. Write a JavaScript function to convert an object into a list of `[key, value]` pairs.
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16. Write a JavaScript function to get a copy of the object where the keys become the values and the values are the keys.
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17. Write a JavaScript function to check whether an object contains a given property.
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18. Write a JavaScript function to check whether a given value is a DOM element.
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