w3resource
JavaScript Exercises

JavaScript: List the properties of a JavaScript object

JavaScript Object: Exercise-1 with Solution

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

Sample Solution: -

HTML Code:

<!DOCTYPE html>
  <html>
  <head>
  <meta charset="utf-8">
  <title>JavaScript program to list the properties of a JavaScript object. </title>
  </head>
  <body>
</body>
  </html>

JavaScript Code:

function _keys(obj) 
 {
    if (!isObject(obj)) return [];
    if (Object.keys) return Object.keys(obj);
    var keys = [];
    for (var key in obj) if (_.has(obj, key)) keys.push(key);
    return keys;
  }
function isObject(obj) 
{
    var type = typeof obj;
    return type === 'function' || type === 'object' && !!obj;
  }
console.log(_keys({red: "#FF0000", green: "#00FF00", white: "#FFFFFF"}));

Sample Output:

["red","green","white"]

Flowchart:

Flowchart: JavaScript - List the properties of a JavaScript object.

Live Demo:

See the Pen javascript-object-exercise-1 by w3resource (@w3resource) on CodePen.


Contribute your code and comments through Disqus.

Previous: javascript Object Eexercises.
Next: Write a JavaScript program to delete the rollno property from the following object. Also print the object before or after deleting the property.

What is the difficulty level of this exercise?