If there is no error, error will be null and data will contain the file contents otherwise err contains the error message. In an asynchronous form, the last argument is always a completion callback. All methods come in synchronous and asynchronous forms. The fs module comes with a bunch of file system methods all packed in one module. If no encoding is provided, the default is null.Ĭallback is a function to call when the file has been read and the contents are ready - it is passed two arguments, error and data. File reading in Node.js can be accomplished through the core built-in fs module, also known as the File System module. Possible encodings are ascii, utf8, and base64. file = (string) filepath of the file to readĮncoding is an optional parameter that specifies the type of encoding to read the file. The easiest way to read the entire contents of a file is with fs.readFile, as follows: fs = require('fs') įs.readFile(file,, )
There are a variety of file system methods, all contained in the fs module. the Fs.readJson method reads and parses the content of a JSON file and returns the resolved JavaScript value: import Fs from package = await Fs.readJson('package.Reading the contents of a file into memory is a very common programming task, and, as with many other things, the Node.js core API provides methods to make this trivial. The package comes with a handy Fs.readJson(path) method. I’m the maintainer of the package providing convenient file system utilities. The easiest way to read the entire contents of a file is with fs. You can import a JSON file using the require from the CommonJS module loader like this: const package = require('./package.json') Reading the contents of a file into memory is a very common programming task, and, as with many other things, the Node.js core API provides methods to make this trivial. It loads the JSON file from disk and detects the need to parse it to a JavaScript object. A nice benefit of the require is that it can read and resolve JSON files, too. It’s a global function that you typically use to import files within other files. The CommonJS module loader comes with the require() function. You can use the package object like you would use any other JavaScript object. filehandle.read (buffer, offset, length, position) filehandle.read ( options) filehandle.read (buffer, options) filehandle.readableWebStream () filehandle.readFile (options) filehandle.readv (buffers, position) filehandle.stat ( options) filehandle.sync () uncate (len) filehandle.
NODEJS READ FILE CODE
Here’s a code sample reading the local package.json from the hard disk and parsing it into a usable JavaScript object: const Fs = require('fs/promises')Ĭonst json = await Fs.readFile('./package.json')
NODEJS READ FILE HOW TO
Use the JSON.parse method to convert the JSON string into a JavaScript object Now that you know how to read YAML files with Node.js, let's see how we can write JavaScript objects/data to a YAML file. We can also use fs.readFile fs file operation for reading file without synchronously. The second function reads the file’s data synchronously. We can use fs.readFileSync to read the file synchronously with the provided file path. The first function reads the data of the file asynchronous.
First function readFile () and another function is readFileSync (). Node.js provides the global JSON class for that. There are two functions to read files in the node js. The next step is to parse the JSON string into a JavaScript value. Related to a JSON file, you’ll then have the JSON content as a string. The simplest way to read a file in Node.js is to use the fs.readFile() method, passing it the file path, encoding and a callback function that will be. Use the Fs.readFile to read the content of a given file. For this we can use the readFile method of the fs class. That would allow us to hand several requests in parallel. That is, to tell Node to read in the file, and then to get a callback when the file-reading has been finished. Node.js provides the fs module to read files from the local hard disk. The 'normal' way in Node.js is probably to read in the content of a file in a non-blocking, asynchronous way.