使用createWriteStream为通过FTP下载的txt文件分配变量

我试图通过FTP下载.txt文件，然后将此文件分配给变量，我可以在代码中稍后编辑文本。

当从Node.js中的createWriteStream创建变量时，不确定如何设置可在FTP代码块之外使用的变量。

如何将这个，txt传递给变量ftpItem，然后在FTP函数外部访问它？

AWS Lambda返回的错误是ftpItem is not defined - 总之，我试图通过FTP下载TXT文件。将其放在AWS Lambda函数的/ tmp /目录中，然后在代码中打开并编辑该文本。

var fullPath = event.line_items[0].meta_data[2].value.tmp_name; 
const extension = path.extname(fullPath); 
const FileName = path.basename(fullPath, extension); 
const FileNameWithExtension = path.basename(fullPath); 

...

async function example() {
    const client = new ftp.Client()
    client.ftp.verbose = true
    try {
        await client.access({
            host: process.env.FTP_HOST,
            user: process.env.FTP_USERNAME,
            password: process.env.FTP_PASSWORD,
        })
        console.log(await client.list())
        await client.download(fs.createWriteStream('/tmp/' + FileNameWithExtension), FileNameWithExtension)
        var ftpItem = FileNameWithExtension.Body.toString('ascii');
        console.log(ftpItem);
    }
    catch(err) {
        console.log(err)
    }
    client.close()
}

...

// Use the variable ftpItem outside of the FTP call
// Also tried the following with the same error above
await client.download(fs.createWriteStream('/tmp/' + FileNameWithExtension), FileNameWithExtension)
        {
          var ftpItem = download.Body.toString('ascii');
        }  

使用更高范围的变量：

var fullPath = event.line_items[0].meta_data[2].value.tmp_name; 
const extension = path.extname(fullPath); 
const FileName = path.basename(fullPath, extension); 
const FileNameWithExtension = path.basename(fullPath); 
let ftpItem
...

async function example() {
    const client = new ftp.Client()
    client.ftp.verbose = true
    try {
        await client.access({
            host: process.env.FTP_HOST,
            user: process.env.FTP_USERNAME,
            password: process.env.FTP_PASSWORD,
        })
        console.log(await client.list())
        await client.download(fs.createWriteStream('/tmp/' + FileNameWithExtension), FileNameWithExtension)
        // asign the variable here
        ftpItem = FileNameWithExtension.Body.toString('ascii');
        console.log(ftpItem);
    }
    catch(err) {
        console.log(err)
    }
    client.close()
}

...

// Use the variable ftpItem outside of the FTP call
// Also tried the following with the same error above
await client.download(fs.createWriteStream('/tmp/' + FileNameWithExtension), FileNameWithExtension)
        {
          // Here you can use ftpItem
          console.log(ftpItem)
        }