FAQ: Node.js Essentials - The Buffer Module

This community-built FAQ covers the “The Buffer Module” exercise from the lesson “Node.js Essentials”.

Paths and Courses
This exercise can be found in the following Codecademy content:

Learn Node.js

FAQs on the exercise The Buffer Module

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After executing this code

const buffer1 = Buffer.from('hello');
const buffer2 = Buffer.from('world');

const bufferArray = [buffer1, buffer2];
const bufferConcat = Buffer.concat(bufferArray);

const bufferString = Buffer.toString(bufferConcat);


I got this output from the terminal:

$ node buffer.js
function Buffer(arg, encodingOrOffset, length) {
  // Common case.
  if (typeof arg === 'number') {
    if (typeof encodingOrOffset === 'string') {
      throw new ERR_INVALID_ARG_TYPE('string', 'string', arg);
    return Buffer.alloc(arg);
  return Buffer.from(arg, encodingOrOffset, length);

Shouldn’t it be helloworld? And why did it output this?

Hey! I’ve just completed the exercise and your code just has a typo at the fourth checkpoint, it should be:

const bufferString = bufferConcat.toString();

instead of:

const bufferString = Buffer.toString(bufferConcat);

As what you want to do is translate the previously created bufferConcat to a string.
Good luck!


Regarding this chapter on the Buffer module: I know this whole lesson is just supposed to cover some ‘essentials’ of Node without going too much in depth, but still, I found it fell short on explaining what would give everything in this exercise its sense: what’s a buffer, in what way it is relevant to Node.js and in what situation we would be brought to use the Buffer module. Like often, Codecademy does a good job of putting the cart before the horse by making us apply a bunch of methods while still leaving us clueless about when, where and why we should apply them…

The first sections of this page helped a bit, in case it can benefit someone else’s understanding: Node.js buffer: A complete guide - LogRocket Blog


Now I understand. Thanks!

1 Like

const bufferAlloc = Buffer.alloc(15, "b"); is useless here, no?

Agree completely, the syntax is not complex, but I feel lost in the deep end this entire lesson with literally zero context. Not sure how I can remember any of this if I have no way to visualize how it could be used.

Why don’t we use the “new” keyword when creating a buffer instance here as we did when we created new event.EventEmitter()?