js indexof 变量

let fruits = ['apple', 'banana', 'cherry', 'date'];

// 查找 'cherry' 的索引
let index = fruits.indexOf('cherry');
console.log(index); // 输出: 2

// 查找不存在的元素 'grape' 的索引
index = fruits.indexOf('grape');
console.log(index); // 输出: -1

// 从指定索引开始查找
index = fruits.indexOf('banana', 1);
console.log(index); // 输出: 1

let items = ['Apple', 'Banana', 'Cherry'];
let searchItem = 'apple';

let index = items.findIndex(item => item.toLowerCase() === searchItem.toLowerCase());
console.log(index); // 输出: 0

let people = [
  { name: 'Alice', age: 25 },
  { name: 'Bob', age: 30 },
  { name: 'Charlie', age: 35 }
];

let personToFind = { name: 'Bob', age: 30 };

let index = people.findIndex(person => 
  person.name === personToFind.name && person.age === personToFind.age
);
console.log(index); // 输出: 1