JSFiddle - React, Tailwind, and code Playground
by Matthew Day
HTML
<form name="check">
<input id="hey" type="text" />
<div id="submit" class="">Submit</div>
</form>
JavaScript
var arr1 = [];
$('#submit').click(function(e) {
e.preventDefault();
var el = $('#hey').val();
if(arr1.indexOf(el) > 0) {
console.log('This value is already in the array.')
} else {
arr1.push(el);
}
console.log(arr1);
});