JSFiddle - React, Tailwind, and code Playground

JavaScript

var bod = $("body"),
    bods = bod[0].style;

console.log(
    bods.background == '', 
    bods.backgroundImage == '', 
    bods.backgroundColor == ''
);

console.log(
    bod.css('background'), '|',
    bod.css('backgroundImage'), '|',
    bod.css('backgroundColor')
);

function isBGDefined(ele){
    var img = $(ele).css('backgroundImage'),
        col = $(ele).css('backgroundColor');
    
    return img != 'none' || (col != 'rgba(0, 0, 0, 0)' && col != 'transparent');
};

console.log(isBGDefined('body'));