String.prototype.indexOf()const paragraph = "I think Ruth's dog is cuter than your dog!"; const searchTerm = "dog"; const indexOfFirst = paragraph.indexOf(searchTerm); console.log(`The index of the first "${searchTerm}" is ${indexOfFirst}`); // 予想される結果: "The index of the first "dog" is 15" console.log( `The index of the second "${searchTerm}" is ${paragraph.indexOf( searchTerm, indexOfFirst + 1, )}`, ); // 予想される結果: "The in
