如何在使用readdir内部的readdir之后向客户端发送数据？

Question

我需要读一个叫做“曲线”的文件夹。很多文件夹都在“曲线”中，我使用readdir来获取它们。在获得文件夹在‘曲线’内，我正在做一个预测，并使用readdir列出文件(文件夹中的文件，即在‘曲线’)。

问题是，我只能访问内部readdir中的变量(我用console.log进行了测试)。

问:我如何访问这些变量并使用res响应客户端。？

我走了这么远：

exports.getInserted = async function (req, res) {

    var teste = await getFilesNames(); // HERE I NEED TO GET THIS FILES NAMES WITH FOLDERS
    console.log(teste); // AND THEM PASSING TO THE CLIENT WITH RES.SEND()

};

function getFilesNames() {
    return new Promise(function (resolve, reject) {

        const chartFolder = './curvas/';
        var fileNames = [];

        fs.readdir(chartFolder, (err, folders) => {

            if (err) {
                reject(new Error("Erro ao ler os arquivos."));
            }
            folders.forEach(folder => {
                fs.readdir(chartFolder + folder, (err, files) => {
                    fileNames = files;
                    console.log(files) // ----- HERE I CAN SEE ALL FILES AND LIST WITH THEIR FOLDERS.
                });
            });
            // I NEED USE resolve(fileNames) HERE, BUT IS EMPTY!!
        });
    });
};

谢谢!

编辑

解决方案:由@omarwaleed引导的

    exports.getInserted = async function (req, res) {

    // Envia os arquivos das pastas de curvas para o cliente.
    var data = await getFilesNames();
    res.status(200).send(data);

};

function getFilesNames() {
    return new Promise(function (resolve, reject) {

        const chartFolder = './curvas/';

        // take care. I've turned it into an async function here
        fs.readdir(chartFolder, async (err, folders) => {

            if (err) {
                reject(new Error("Erro ao ler os arquivos."));
            }
            let promiseArray = [];
            folders.forEach(folder => {
                promiseArray.push(
                    new Promise((resolve, reject) => fs.readdir(chartFolder + folder, (err, files) => {
                        if (err) {
                            reject(err);
                        }
                        resolve({
                            folder: folder,
                            files: files
                        });
                    }))
                )
            });
            let results = await Promise.all(promiseArray);
            resolve(results)
        });
    });
};

Answer 1

使用解析代替注释，// I NEED USE resolve(fileNames) HERE, BUT IS EMPTY!!将导致一个未定义的fs.readdir语句，因为第二个fs.readdir将异步运行，这意味着在代码解析后将读取目录。为了解决这个问题，我建议您将fs.readdir包装成承诺，在这里您可以等待所有文件的读取并解决响应。

下面是您的函数的样子

function getFilesNames() {
    return new Promise(function (resolve, reject) {

        const chartFolder = './curvas/';
        var fileNames = [];

        // take care. I've turned it into an async function here
        fs.readdir(chartFolder, async (err, folders) => {

            if (err) {
                reject(new Error("Erro ao ler os arquivos."));
            }
            let promiseArray = [];
            folders.forEach( folder => {
            promiseArray.push(
              new Promise((resolve, reject)=>fs.readdir(chartFolder + folder, (err, files)=>{
                if(err){
                  reject(err)
                }
                resolve(files)
              }))
            )
        });
        let results = await Promise.all(promiseArray);
            resolve(results)
        });
    });
};