映射错误:无法读取未定义的属性'map‘

let myArray;

// 假设这里有可能 myArray 被赋值为 undefined 或其他非数组值
if (Array.isArray(myArray)) {
    let newArray = myArray.map(item => item * 2);
} else {
    console.error('myArray is not an array or is undefined');
}

let myArray = someFunctionThatMightReturnUndefined() || [];
let newArray = myArray.map(item => item * 2);

async function fetchData() {
    let response = await fetch('https://api.example.com/data');
    let data = await response.json();
    
    if (Array.isArray(data)) {
        let processedData = data.map(item => item.value);
        console.log(processedData);
    } else {
        console.error('Data is not an array:', data);
    }
}

fetchData();