收到不一致的静音命令TypeError: fn不是函数

let fn = function() {
    console.log('This is a function');
};

// 调用函数
fn();

function outer() {
    let fn = function() {
        console.log('This is a function');
    };

    // 调用函数
    fn();
}

outer();

let fn = function() {
    console.log('This is a function');
};

if (typeof fn === 'function') {
    fn();
} else {
    console.error('fn is not a function');
}

let fn = function() {
    console.log('This is a function');
};

console.log(typeof fn); // 输出: function

fn();

function executeFunction(fn) {
    if (typeof fn === 'function') {
        fn();
    } else {
        console.error('fn is not a function');
    }
}

let validFn = function() {
    console.log('This is a valid function');
};

let invalidFn = 'This is not a function';

executeFunction(validFn); // 输出: This is a valid function
executeFunction(invalidFn); // 输出: fn is not a function