JavaScript TypeError – Can’t access property “X” of “Y”

0 0 1 minute read

This JavaScript exception can’t access property occurs if property access was performed on undefined or null values.

Message:

TypeError: Unable to get property {x} of undefined or 
           null reference (Edge)
TypeError: can't access property {x} of {y} (Firefox)
TypeError: {y} is undefined, can't access property {x} 
           of it (Firefox)
TypeError: {y} is null, can't access property {x} of it
           (Firefox)

Examples:

TypeError: x is undefined, can't access property "prop" 
           of it 
TypeError: x is null, can't access property "prop" of it 
TypeError: can't access property "prop" of undefined
TypeError: can't access property "prop" of null

Error Type:

TypeError

Cause of Error: The property access was performed on any of the undefined or null values in the code.

Example 1: In this example, the GFG is undefined, So the error has occurred.

HTML

let GFG = undefined;
GFG.substring(3); // error here

Output(in console):

TypeError: Unable to get property 'substring' of undefined or null reference

Example 2: In this example, the GFG is null, So the error has occurred.

Javascript

let GFG = null;
GFG.substring(3); // error here

Output(in console):

TypeError: Unable to get property 'substring' of undefined or null reference

Whether you’re preparing for your first job interview or aiming to upskill in this ever-evolving tech landscape, zambiatek Courses are your key to success. We provide top-quality content at affordable prices, all geared towards accelerating your growth in a time-bound manner. Join the millions we’ve already empowered, and we’re here to do the same for you. Don’t miss out – check it out now!