let shoppingList: string[] = [ 'Eggs', 'Milk', 'Fish', 'Apple', 'Bread', 'Chicken', ]; function isThere(arr: string[]): void { let there1: boolean = arr.indexOf('Milk') > -1; let there2: boolean = arr.indexOf('Banana') > -1; console.log(there1); console.log(there2); } isThere(shoppingList);