Using the Buffer `toString()` Function in Node.js
Node.js buffers are objects that store arbitrary binary data. Buffers have a toString() method that you can use to convert the buffer
to a string.
By default, toString() converts the buffer to a string using UTF8 encoding. For example, if you create a buffer
from a string using Buffer.from(), the toString() function gives you the original string back.
const buf = Buffer.from('Hello, World', 'utf8');
buf.toString(); // 'Hello, World'The encoding Parameter
The toString() method's first parameter is a string called encoding. It determines what format Node.js uses to express
the raw data. The default value is 'utf8'.
const fs = require('fs');
const buf = fs.readFileSync('./package.json');
buf.toString('utf8'); // '{ "name": "masteringjs.io", ...}'Node.js supports numerous different encodings for buffers. The most commonly used are:
- 'utf8'
- 'hex'
- 'base64'
For example, by calling .toString('hex'), you get a string representation of the buffer where each byte is encoded
as 2 hexadecimal characters.
const fs = require('fs');
const buf = fs.readFileSync('./package.json');
buf.toString('hex'); // '7b0a2020...'Which encoding is correct depends on your use case and the data stored in the buffer. Typically Buffer#toString() is
used for debugging and trying to figure out what the contents of the buffer mean. If that's your use case, try all
3 different encodings and see if any of them look familiar.
One common use case for .toString() is converting a file to base64 so it can be used as an email attachment. Here's how you can convert a file to base64 encoding using Node.js:
const fs = require('fs');
const buf = fs.readFileSync('./package.json');
buf.toString('base64'); // 'ewogICJuYW1lI...'