DEV Community: Roberto Tonino

How to work in multiple branches of the same repo at the same time

Roberto Tonino — Fri, 28 Jan 2022 12:17:19 +0000

You can use Git worktrees 🌲 to achieve so. Just cd in a git repo and run

git worktree add <filesystem-location> <branch>

and git will create a new folder in the path <filesystem-location> and checkout the branch <branch> in that folder.

For instance:

git worktree add ../app-4.2.0 production-4.2.0

Now you can manage 2 copies of the same repo at the same time 💏🏽

Full reference: https://git-scm.com/docs/git-worktree

How to fix express-js CORS requests that use req.session.id

Roberto Tonino — Wed, 05 Jan 2022 16:32:01 +0000

I had a problem: I had an express-js server serving the frontend by directly serving an HTML page.
For the frontend development, I was using a dev script which, using Rollup, was bundling js (and css and imgs and etc...) in a single file. I decided to switch to Vite for better developer experience, but I faced a problem I didn't expect: when setting up CORS permissions (by using express' middleware), the frontend did not work properly. I will not go into details of the code.

The problem was that the server used, for some requests, the req.session.id string as a common ground for storing some (important!) information. In the previous setting, this string remained unique among all the requests coming from the frontend, but at this point it was not the case anymore.

To resolve this problem, it was simply necessary to add the following option when calling the fetch function (to
all of them):

fetch('endpoint', {
    credentials: 'include',
})

(And obviously enabling credentials in the CORS middleware:)

app.use(
    cors({
        credentials: true,
    }),
)

This fix, in some way that I'm still not 100% sure, helps keeping the same req.session.id by passing in the HTTP
headers the necessary cookies.

1 small tip to improve your code readability

Roberto Tonino — Fri, 25 Sep 2020 12:10:24 +0000

(Kevin Du photo on Pexels)

Code readability is important.

When you find yourself in situations like this one:

function doSomething() {
  // some code...
  let needToDoALotOfThings = /* test */

  if (needToDoALotOfThings) {
    /*

       A good amount of code

    */
  }
}

you can refactor it in this way:

function doSomething() {
  // some code...
  let needToDoALotOfThings = /* test */

  if (!needToDoALotOfThings) return

  /*

     A good amount of code

  */

}

or, even better:

function doSomething() {
  // some code...
  let needToDoALotOfThings = /* test */

  if (!needToDoALotOfThings) throw new Error(/* error message */)

  /*

     A good amount of code

  */

}

The difference is slight but significant. By using this approach, you'll have (at least) 2 advantages:

1 less indentation level, that is always good;
Your condition is shrinked in 1 line of code, making the code easier to read in future reviews.

You obviously can't use this approach everywhere, it depends on the situation (as always), but it's a small correction that can save a bit of brain cells to the person that will read that snippet of code in the future.