JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" id="1" value="10" onclick="check(this);" />
<button type="button" class="menos" id="decrement1">-</button>
<input type="text" class="txt" value="1" size="4" disabled="disabled" id="text-field1"/>
<button type="button" class="mais" id="increment1">+</button> 
<div style="clear: both;"></div>

<input type="checkbox" id="2" value="10" onclick="check(this);" />
<button type="button" class="menos" id="decrement2">-</button>
<input type="text" class="txt" value="1" size="4" disabled="disabled" id="text-field2"/>
<button type="button" class="mais" id="increment2">+</button> 
<div style="clear: both;"></div>

JavaScript

var max_unit=5,
    valor=[];
function id(el){
    return document.getElementById(el);
}

function check(checkbox){
    
    if(checkbox.checked){	
	 	valor[checkbox.id] = Number(id('text-field' + checkbox.id).value);	
		 /*quantidade*/
		
		 /*increment button*/
		 id('increment'+ checkbox.id).onclick = function(){
             console.log(valor);
             if( id('text-field'+ checkbox.id).value < max_unit)
                 valor[checkbox.id]++;
             id('text-field' + checkbox.id).value = valor[checkbox.id];	
		 }
		 
	 	 /*decrement button*/
		 id('decrement'+ checkbox.id).onclick = function(){
             console.log(valor);
             if(id('text-field'+ checkbox.id).value > 1)
                 valor[checkbox.id]--;
            id('text-field' + checkbox.id).value = valor[checkbox.id];
		}
		
		
		 
}
/*end if*/
		else{
		valor[checkbox.id]=1;
		document.getElementById('decrement'+checkbox.id).disabled=true;
	}
	
}