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Reading files with Node

The Valley of Code

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How to read files using Node and the `fs` module

The simplest way to read a file in Node is to use the fs.readFile() method, passing it the file path and a callback function that will be called with the file data (and the error):

const fs = require('fs')

fs.readFile('/Users/flavio/test.txt', (err, data) => {
  if (err) {

Alternatively, you can use the synchronous version fs.readFileSync():

const fs = require('fs')

try {
  const data = fs.readFileSync('/Users/flavio/test.txt', 'utf8')
} catch (err) {

The default encoding is utf8, but you can specify a custom encoding using a a second parameter.

Both fs.readFile() and fs.readFileSync() read the full content of the file in memory before returning the data.

This means that big files are going to have a major impact on your memory consumption and speed of execution of the program.

In this case, a better option is to read the file content using streams.

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