array of objects how to check if property has duplicate
var yourArray = [ {Index: 1, Name: "Farley, Charley", EmployeeCode: "12", PaymentType: "Void", CheckDate: "01/04/2012"}, {Index: 2, Name: "Farley, Charley", EmployeeCode: "12", PaymentType: "Void", CheckDate: "01/04/2012"}, {Index: 3, Name: "Tarley, Charley", EmployeeCode: "12", PaymentType: "Void", CheckDate: "01/04/2012"} ]; unique = [...new Set(yourArray.map(propYoureChecking => propYoureChecking.Name))]; if (unique.length === 1) { console.log(unique); }