JSFiddle - React, Tailwind, and code Playground

HTML

<label for="checkboxtest" id="lbl">This is a label</label><input type="checkbox" id="checkboxtest">

JavaScript

if(typeof window['$'] !== 'undefined' || typeof window['jQuery'] !== 'undefined') {
	jQuery(function(){
		// Saving the old instance so this can do stuff when we don't need it.
		jQuery.fn.ZAGREUSoldoldoldVal = jQuery.fn.val;
		// Making our own value function!
		jQuery.fn.val = function(value){
			// Check if it's  a checkbox. If so, do our magic!
			if(typeof value !== 'undefined' && (this[0] instanceof HTMLInputElement && this[0].getAttribute('type') == 'checkbox')) {
				// Saving our instance for scoping
				var that = this;
				// Generic setvalue function to prevent code duplication.
				var setval = function(bool) {
					var oldbool = that[0].checked;
					that[0].checked = bool;
					// Remove this if you don't want a trigger whent he value changes.
					if(oldbool !== bool) {
						that.trigger('change');
					}
				}
				// All possible values that can be entered. False means unchecked, true means checked.
				// Modify as needed.
				switch(value) {
					case 'j' : setval(true);break;
					case 'y' : setval(true); break;
					case 'n' : setval(false); break;
					case true : setval(true);break;
					case false : setval(false);break;
					case 1 : setval(true);break;
					case 0 : setval(false);break;
					case 'checked' : setval(true);break;
					case '' : setval(false);break;
				} 
			}
			// We didn't get an argument, so we assume we want to read the data
			else if(typeof value === 'undefined' && (this[0] instanceof HTMLInputElement && this[0].getAttribute('type') == 'checkbox')) {
				return this[0].checked// ? 'y' : 'n';//<-- optional string return... depends on what you want
			}
			else{
				// Default handling of the val function.
				return typeof value !== 'undefined' ? jQuery(this).ZAGREUSoldoldoldVal(value) : jQuery(this).ZAGREUSoldoldoldVal();
			}
		}; 
	});
}

var checkbox = $('#checkboxtest');
var label = $('#lbl');
function switcheroo() {
    checkbox.val(true);
    label.text('checbox checked = '+checkbox.val());    
   ...