Looping through files in a folder Node.JS
Read all folders in a directory
const readAllFolder = (dirMain) => {
const readDirMain = fs.readdirSync(dirMain);
console.log(dirMain);
console.log(readDirMain);
readDirMain.forEach((dirNext) => {
console.log(dirNext, fs.lstatSync(dirMain + "/" + dirNext).isDirectory());
if (fs.lstatSync(dirMain + "/" + dirNext).isDirectory()) {
readAllFolder(dirMain + "/" + dirNext);
}
});
};
Older answer with callbacks
You want to use the fs.readdir function to get the directory contents and the fs.rename function to actually do the renaming. Both these functions have synchronous versions if you need to wait for them to finishing before running the code afterwards.
I wrote a quick script that does what you described.
var fs = require('fs');
var path = require('path');
// In newer Node.js versions where process is already global this isn't necessary.
var process = require("process");
var moveFrom = "/home/mike/dev/node/sonar/moveme";
var moveTo = "/home/mike/dev/node/sonar/tome"
// Loop through all the files in the temp directory
fs.readdir(moveFrom, function (err, files) {
if (err) {
console.error("Could not list the directory.", err);
process.exit(1);
}
files.forEach(function (file, index) {
// Make one pass and make the file complete
var fromPath = path.join(moveFrom, file);
var toPath = path.join(moveTo, file);
fs.stat(fromPath, function (error, stat) {
if (error) {
console.error("Error stating file.", error);
return;
}
if (stat.isFile())
console.log("'%s' is a file.", fromPath);
else if (stat.isDirectory())
console.log("'%s' is a directory.", fromPath);
fs.rename(fromPath, toPath, function (error) {
if (error) {
console.error("File moving error.", error);
} else {
console.log("Moved file '%s' to '%s'.", fromPath, toPath);
}
});
});
});
});
Tested on my local machine.
node testme.js
'/home/mike/dev/node/sonar/moveme/hello' is a file.
'/home/mike/dev/node/sonar/moveme/test' is a directory.
'/home/mike/dev/node/sonar/moveme/test2' is a directory.
'/home/mike/dev/node/sonar/moveme/test23' is a directory.
'/home/mike/dev/node/sonar/moveme/test234' is a directory.
Moved file '/home/mike/dev/node/sonar/moveme/hello' to '/home/mike/dev/node/sonar/tome/hello'.
Moved file '/home/mike/dev/node/sonar/moveme/test' to '/home/mike/dev/node/sonar/tome/test'.
Moved file '/home/mike/dev/node/sonar/moveme/test2' to '/home/mike/dev/node/sonar/tome/test2'.
Moved file '/home/mike/dev/node/sonar/moveme/test23' to '/home/mike/dev/node/sonar/tome/test23'.
Moved file '/home/mike/dev/node/sonar/moveme/test234' to '/home/mike/dev/node/sonar/tome/test234'.
Update: fs.promises functions with async/await
Inspired by ma11hew28's answer (shown here), here is the same thing as above but with the async functions in fs.promises. As noted by ma11hew28, this may have memory limitations versus fs.promises.opendir added in v12.12.0.
Quick code below.
//jshint esversion:8
//jshint node:true
const fs = require( 'fs' );
const path = require( 'path' );
const moveFrom = "/tmp/movefrom";
const moveTo = "/tmp/moveto";
// Make an async function that gets executed immediately
(async ()=>{
// Our starting point
try {
// Get the files as an array
const files = await fs.promises.readdir( moveFrom );
// Loop them all with the new for...of
for( const file of files ) {
// Get the full paths
const fromPath = path.join( moveFrom, file );
const toPath = path.join( moveTo, file );
// Stat the file to see if we have a file or dir
const stat = await fs.promises.stat( fromPath );
if( stat.isFile() )
console.log( "'%s' is a file.", fromPath );
else if( stat.isDirectory() )
console.log( "'%s' is a directory.", fromPath );
// Now move async
await fs.promises.rename( fromPath, toPath );
// Log because we're crazy
console.log( "Moved '%s'->'%s'", fromPath, toPath );
} // End for...of
}
catch( e ) {
// Catch anything bad that happens
console.error( "We've thrown! Whoops!", e );
}
})(); // Wrap in parenthesis and call now
fs.readdir(path[, options], callback) (which Mikey A. Leonetti used in his answer) and its variants (fsPromises.readdir(path[, options]) and fs.readdirSync(path[, options])) each reads all of a directory's entries into memory at once. That's good for most cases, but if the directory has very many entries and/or you want to lower your application's memory footprint, you could instead iterate over the directory's entries one at a time.
Asynchronously
Directories are async iterable, so you could do something like this:
const fs = require('fs')
async function ls(path) {
const dir = await fs.promises.opendir(path)
for await (const dirent of dir) {
console.log(dirent.name)
}
}
ls('.').catch(console.error)
Or, you could use dir.read() and/or dir.read(callback) directly.
Synchronously
Directories aren't sync iterable, but you could use dir.readSync() directly. For example:
const fs = require('fs')
const dir = fs.opendirSync('.')
let dirent
while ((dirent = dir.readSync()) !== null) {
console.log(dirent.name)
}
dir.closeSync()
Or, you could make directories sync iterable. For example:
const fs = require('fs')
function makeDirectoriesSyncIterable() {
const p = fs.Dir.prototype
if (p.hasOwnProperty(Symbol.iterator)) { return }
const entriesSync = function* () {
try {
let dirent
while ((dirent = this.readSync()) !== null) { yield dirent }
} finally { this.closeSync() }
}
if (!p.hasOwnProperty(entriesSync)) { p.entriesSync = entriesSync }
Object.defineProperty(p, Symbol.iterator, {
configurable: true,
enumerable: false,
value: entriesSync,
writable: true
})
}
makeDirectoriesSyncIterable()
And then, you could do something like this:
const dir = fs.opendirSync('.')
for (const dirent of dir) {
console.log(dirent.name)
}
Note: "In busy processes, use the asynchronous versions of these calls. The synchronous versions will block the entire process until they complete, halting all connections."
References:
- Node.js Documentation: File System:
Class fs.Dir - Node.js source code:
fs.Dir - GitHub: nodejs/node: Issues: streaming / iterative fs.readdir #583