JSFiddle - React, Tailwind, and code Playground

by jordan_josh3184

HTML

<button name="save" onclick="hasDuplicateOrderNum()" />

JavaScript

var data = [{
    "Id": "hello",
    "orderNum": "world"
}, {
    "Id": "abc",
    "oderNum": "xyz"
},
, {
    "Id": "hello",
    "orderNum": "world"
}]

function hasDuplicateOrderNum(data){
	for (var i = 0; i < data.length - 1; i++) {
	    if (data[i + 1].orderNum == data[i].orderNum) {
          alert(data[i].orderNum);
	        return true;
	    }
	}
}