fs – Page 3 – Tarik Billa

How to close a readable stream (before end)?

December 17, 2022 by Tarik

Edit: Good news! Starting with Node.js 8.0.0 readable.destroy is officially available: https://nodejs.org/api/stream.html#stream_readable_destroy_error ReadStream.destroy You can call the ReadStream.destroy function at any time. var fs = require(“fs”); var readStream = fs.createReadStream(“lines.txt”); readStream .on(“data”, function (chunk) { console.log(chunk); readStream.destroy(); }) .on(“end”, function () { // This may not been called since we are destroying the stream // … Read more

Writing JSON object to a JSON file with fs.writeFileSync

November 30, 2022 by Tarik

You need to stringify the object. fs.writeFileSync(‘../data/phraseFreqs.json’, JSON.stringify(output));

Copy folder recursively in Node.js

November 26, 2022 by Tarik

It looks like ncp and wrench both are no longer maintained. Probably the best option is to use fs-extra The Developer of Wrench directs users to use fs-extra as he has deprecated his library copySync & moveSync both will copy and move folders even if they have files or subfolders and you can easily move … Read more

Using filesystem in node.js with async / await

October 15, 2022 by Tarik

Native support for async/await fs functions since Node 11 Since Node.JS 11.0.0 (stable), and version 10.0.0 (experimental), you have access to file system methods that are already promisify’d and you can use them with try catch exception handling rather than checking if the callback’s returned value contains an error. The API is very clean and … Read more

How to create full path with node’s fs.mkdirSync?

October 6, 2022 by Tarik

Update NodeJS version 10.12.0 has added a native support for both mkdir and mkdirSync to create a directory recursively with recursive: true option as the following: fs.mkdirSync(targetDir, { recursive: true }); And if you prefer fs Promises API, you can write fs.promises.mkdir(targetDir, { recursive: true }); Original Answer Create directories recursively if they do not … Read more

Node.js check if file exists

October 4, 2022 by Tarik

Consider opening the file directly, to avoid race conditions: const fs = require(‘fs’); fs.open(‘foo.txt’, ‘r’, function (err, fd) { // … }); Using fs.existsSync: if (fs.existsSync(‘foo.txt’)) { // … } Using fs.stat: fs.stat(‘foo.txt’, function(err, stat) { if (err == null) { console.log(‘File exists’); } else if (err.code === ‘ENOENT’) { // file does not exist … Read more

Write / add data in JSON file using Node.js

October 2, 2022 by Tarik

If this JSON file won’t become too big over time, you should try: Create a JavaScript object with the table array in it var obj = { table: [] }; Add some data to it, for example: obj.table.push({id: 1, square:2}); Convert it from an object to a string with JSON.stringify var json = JSON.stringify(obj); Use … Read more

Get file name from absolute path in Nodejs?

September 20, 2022 by Tarik

Use the basename method of the path module: path.basename(‘/foo/bar/baz/asdf/quux.html’) // returns ‘quux.html’ Here is the documentation the above example is taken from.

Node.js check if path is file or directory

September 13, 2022 by Tarik

The following should tell you. From the docs: fs.lstatSync(path_string).isDirectory() Objects returned from fs.stat() and fs.lstat() are of this type. stats.isFile() stats.isDirectory() stats.isBlockDevice() stats.isCharacterDevice() stats.isSymbolicLink() // (only valid with fs.lstat()) stats.isFIFO() stats.isSocket() NOTE: The above solution will throw an Error if; for ex, the file or directory doesn’t exist. If you want a true or false … Read more

How to download a file with Node.js (without using third-party libraries)?

September 10, 2022 by Tarik

You can create an HTTP GET request and pipe its response into a writable file stream: const http = require(‘http’); // or ‘https’ for https:// URLs const fs = require(‘fs’); const file = fs.createWriteStream(“file.jpg”); const request = http.get(“http://i3.ytimg.com/vi/J—aiyznGQ/mqdefault.jpg”, function(response) { response.pipe(file); // after download completed close filestream file.on(“finish”, () => { file.close(); console.log(“Download Completed”); }); … Read more