如何在javascript中引用数组设置内容

let fruits = ['Apple', 'Banana'];
console.log(fruits[0]); // 输出: Apple

// 设置数组的第一个元素
fruits[0] = 'Orange';
console.log(fruits[0]); // 输出: Orange

let arr = [1, 2, 3];
console.log(arr[-1]); // 输出: undefined
console.log(arr[10]); // 输出: undefined

function safeGet(arr, index) {
    return index >= 0 && index < arr.length ? arr[index] : undefined;
}

console.log(safeGet(arr, -1)); // 输出: undefined
console.log(safeGet(arr, 10)); // 输出: undefined

let arr1 = [1, 2, 3];
let arr2 = arr1;
arr2[0] = 'a';

console.log(arr1); // 输出: ['a', 2, 3]
console.log(arr2); // 输出: ['a', 2, 3]

let arr1 = [1, 2, 3];
let arr2 = arr1.slice();
let arr3 = [...arr1];

arr2[0] = 'a';
arr3[0] = 'b';

console.log(arr1); // 输出: [1, 2, 3]
console.log(arr2); // 输出: ['a', 2, 3]
console.log(arr3); // 输出: ['b', 2, 3]