如何纠正未定义TypeError字符串

function myFunction() {
    console.log('Function is defined');
}

myFunction(); // 正确调用

let myFunction;

function defineFunction() {
    myFunction = function() {
        console.log('Function is defined inside another function');
    };
}

defineFunction();
myFunction(); // 正确调用

let myFunction;

if (typeof myFunction === 'function') {
    myFunction();
} else {
    console.log('myFunction is not defined');
}

let myFunction;

try {
    myFunction();
} catch (e) {
    if (e instanceof TypeError) {
        console.log('TypeError: ' + e.message);
    } else {
        console.log('An unexpected error occurred: ' + e.message);
    }
}