Quick Reference
The delete operator deletes a property from an object. It deletes both the value of the property and the property itself.
<!-- html element to place output -->
<p id="my_output"></p>After deletion, the property cannot be used before it is added back again. In the following, after deletion, the property will return as “undefined”.
// object
const my_family = {
first_name:'Johnny',
age:9
};
// delete operator
delete my_family.age;
// output to HTML element
document.getElementById('my_output').innerHTML = my_family.first_name + ' is ' + my_family.age + ' years old.';Output
Johnny is undefined years old.JavaScript Notes:
- When using JavaScript, single or double quotation marks are acceptable and work identically to one another; choose whichever you prefer, and stay consistent
- JavaScript is a case-sensitive language; firstName is NOT the same as firstname
- Arrays count starting from zero NOT one; so item 1 is position [0], item 2 is position [1], and item 3 is position [2] … and so on
- JavaScript variables must begin with a letter, $, or _
- JavaScript variables are case sensitive (x is not the same as X)
We’d like to acknowledge that we learned a great deal of our coding from W3Schools and TutorialsPoint, borrowing heavily from their teaching process and excellent code examples. We highly recommend both sites to deepen your experience, and further your coding journey. We’re just hitting the basics here at 1SMARTchicken.