Node.js fs.WriteStream行为异常

我希望下面的代码打印出来

Finished writing GB translations
Finished writing DE translations
Finished writing US translations

但它却打印出来了

Finished writing DE translations
Finished writing DE translations
Finished writing DE translations

代码：

除此之外，尽管它似乎工作正常，但一切都按照预期写入了gb.json、de.json和us.json。这是为什么？

语言在for循环中每次都被覆盖，但是.on'finish'异步执行。所以language='DE'实际上首先发生，然后所有的'finish'事件发生，所以它将打印出设置为最后一个的任何'language'

有很多方法可以解决这个问题，但最简单/需要最少更改的方法是只使用let，如：

这将为循环的每个迭代定义语言的范围。

ah当然，经典的var错误，感谢您指出这一点

try {
    fs.mkdirSync('./locales');
} catch(e) {
    console.log('Info: Locales directory already exists');
}

jsonDefs = {
             GB: {"Item does not exist": "Item does not exist"},
             DE: {"Item does not exist": "Artikel existiert nicht"}, 
             US: {"Item does not exist": "Item does naaht exist"}
           };

for(language in jsonDefs){
    const fileName = `${language.toLowerCase()}.json`;
    const writeStream = fs.createWriteStream(`./locales/${fileName}`);
    writeStream.on('finish', function(){ console.log(`Finished writing ${language} translations`); });
    writeStream.on('error', function(err){
      console.log(`Error writing to ${fileName}: ${err}`);
    });
    writeStream.write(JSON.stringify(jsonDefs[language]), () => writeStream.end());
}

for (let language in jsonDefs) {