xnv/src/server/backend/notes.js

const path = require("path");
const fs = require("fs");

function listNotesInDirectory(directoryPath = "") {
    return new Promise(function(resolve, reject) {
        fs.readdir(directoryPath, function(err, files) {
            if (err) return reject(err);

            resolve(
                files
                    .map(fPath => ({
                        ext: path.extname(fPath),
                        name: fPath,
                        title: path.basename(fPath, path.extname(fPath)),
                        path: path.join(directoryPath, fPath)
                    }))
                    .filter(
                        ({ ext }) =>
                            ext === ".md" || ext === ".txt" || ext === ".utf8"
                    )
            );
        });
    });
}

function getNoteTime(fullPath) {
    return new Promise((a, r) => {
        fs.stat(fullPath, (err, stats) => {
            if (err) return r(err);

            a({
                lastModified: stats.mtime,
                created: stats.ctime,
                size: stats.size
            });
        });
    });
}

function getNoteContent(fullPath) {
    return new Promise((a, r) =>
        fs.readFile(fullPath, "utf8", (err, data) => {
            if (err) return r(err);
            a({ content: data });
        })
    );
}

async function loadNotesInDirectory(directoryPath = "") {
    const files = await listNotesInDirectory(directoryPath);

    return await Promise.all(
        files.map(async ({ path, title, ext }) => {
            const [noteTime, noteContent] = await Promise.all([
                getNoteTime(path),
                getNoteContent(path)
            ]);

            return {
                path,
                title,
                ...noteTime,
                ...noteContent
            };
        })
    );
}

async function saveNoteInDirectory(
    { directory, defaultExtension },
    { title, content }
) {
    let fullPath = path.join(directory, `${title}.${defaultExtension}`);

    const match = (await listNotesInDirectory(directory)).filter(
        f => f.title === title
    );

    if (match && match.length > 0) fullPath = match[0].path;
    console.log("tryint to write note: ", fullPath, " - ", match);

    return Promise.all([
        new Promise((a, r) => {
            fs.writeFile(fullPath, content, "utf8", err => {
                if (err) return r(err);
                a();
            });
        })
    ]);
}

module.exports = {
    loadNotesInDirectory,
    saveNoteInDirectory
};