JSFiddle - React, Tailwind, and code Playground

HTML

<input id="foo">
    <div id="myDiv"></div>

JavaScript

$scope = {};

//on keydown...
document.getElementById("foo").onkeydown = function() {    
    clearTimeout( $scope.delay );
    $scope.delay = setTimeout( $scope.lookup, 1000);
    document.getElementById("myDiv").innerHTML = "Someone is typing";
}

$scope.lookup = function() {
    document.getElementById("myDiv").innerHTML = "Nobody is typing";
}

$scope.lookup();