JSFiddle - React, Tailwind, and code Playground
JavaScript
var v = 0;
alert("if v is 0 output: "+ (v == 0) );
setTimeout(function(){
v = 1;
alert("if v is 1 Output: "+ (v == 0) );
}, 1000);
var v = 0;
alert("if v is 0 output: "+ (v == 0) );
setTimeout(function(){
v = 1;
alert("if v is 1 Output: "+ (v == 0) );
}, 1000);