Node.js : Asynchronously Read from Files
Use the filesystem module for all file operations:
const fs = require('fs');
With Encoding
In this example, read hello.txt
from the directory /tmp. This operation will be completed in the background and the callback occurs on completion or failure:
fs.readFile('/tmp/hello.txt', { encoding: 'utf8' }, (err, content) => { // If an error occurred, output it and return if(err) return console.error(err); // No error occurred, content is a string console.log(content);});
Without Encoding
Read the binary file binary.txt
from the current directory, asynchronously in the background. Note that we do not set the 'encoding' option - this prevents Node.js from decoding the contents into a string:
fs.readFile('binary', (err, binaryContent) => { // If an error occurred, output it and return if(err) return console.error(err); // No error occurred, content is a Buffer, output it in // hexadecimal representation. console.log(content.toString('hex'));});
Relative paths
Keep in mind that, in general case, your script could be run with an arbitrary current working directory. To address
a file relative to the current script, use __dirname
or __filename
:
fs.readFile(path.resolve(__dirname, 'someFile'), (err, binaryContent) => { //Rest of code}
With all that being said, I highly recommend you keep learning!
Thank you for reading this article. Please feel free to connect with me on LinkedIn and Twitter.
Original Link: https://dev.to/rajeshkumaryadavdotcom/node-js-asynchronously-read-from-files-1hb1
Dev To
An online community for sharing and discovering great ideas, having debates, and making friendsMore About this Source Visit Dev To