有没有办法在switch语句中输入所有大小写？

function processInput(input) {
    // 将输入转换为小写
    const lowerCaseInput = input.toLowerCase();

    switch (lowerCaseInput) {
        case 'apple':
            console.log('It is an apple.');
            break;
        case 'banana':
            console.log('It is a banana.');
            break;
        case 'orange':
            console.log('It is an orange.');
            break;
        default:
            console.log('Unknown fruit.');
    }
}

// 测试不同大小写的输入
processInput('Apple');  // 输出: It is an apple.
processInput('BANANA'); // 输出: It is a banana.
processInput('oRanGe'); // 输出: It is an orange.
processInput('grape');  // 输出: Unknown fruit.