为什么'value.length‘是未定义的？(STS)

async function getValue() {
    // 模拟异步操作
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve("Hello, World!");
        }, 1000);
    });
}

async function fetchData() {
    let value = await getValue();
    if (value !== undefined) {
        console.log(value.length); // 输出: 13
    } else {
        console.log("Value is undefined");
    }
}

fetchData();