JavaScript console gives unexpected error message.

[MJP8]

I am making a game with JavaScript classes and objects (what this repo is for). This is a sample of my code that is having problems:

let text_object = {
    left: $('.enemy').css('left'),
    top: $('enemy').css('top'),
    width: $('.enemy').css('width'),
    height: $('.enemy').css('height')
}
text_object.left.replace('px', '');
text_object.left = parseInt(text_object.left);
text_object.top.replace('px', '');
text_object.top = parseInt(text_object.top);
text_object.width.replace('px', '');
text_object.width = parseInt(text_object.width);
text_object.height.replace('px', '');
text_object.height = parseInt(text_object.height);
enemy.moveToX = Math.round(Math.random() * (($(window).width() - text_object.left) - text_object.width));
enemy.moveToY = Math.round(Math.random() * (($(window).height() - text_object.top) - text_object.height));

The error message in the console is Uncaught TypeError: Cannot read property 'replace' of undefined. What does this mean and what do I need to fix? Here is the whole file

/cc @elijahparker

[MJP8]

@elijahparker fixed it.