🐤🥇 Jasper de Jager

Posted on Apr 20, 2021 • Updated on Apr 30, 2021

✔||🤢 Commit or Vomit | checks.some()

#javascript #programming #webdev #discuss

It's Tuesday!

Time for a new ✔||🤢 Commit or Vomit! This time it is about using [].some(check ⇒ !check). What do you think of the following code?

const checks = [
    data.age > 18,
    data.username.length > 6    
];
if(data.isNewUser) {
    checks.push(data.email !== undefined)
} else {
    checks.push(data.deleted === false)
}

const isInvalid = checks.some(check => !check);

[].some(true) ✔||🤢?

❤: Commit (I'd commit something like this)
🏷: Vomit (we all know unicorns don't vomit)
🦄: Like your post please continue this series!

Let's vote! 😊

Photo by Nik Shuliahin on Unsplash

Top comments (17)

Anner Visser • Apr 20 '21

I quite like the idea (and .some and .every are lovely), but this implementations is somewhat misleading to read:
All the checks are always performed at the time they're added, even though the power in some is that it break;s after the first hit.

I think this is a good opportunity for some higher level functions:

const checks = [
    (data) => data.age > 18,
    (data) => data.username.length > 6,
    (data) => {
        if (data.isNewUser) {
            return data.email !== undefined;
        } else {
            return  data.deleted === false;
        }
    }
];

const isInvalid = checks.some(check => !check(data));

Overall I like the idea, but I think it will seldom be sufficient to deal with just a boolean as output. And if it is that simple, I'd prefer good ol' if/else.

So it's a 🤢 from me

𒎏Wii 🏳️‍⚧️ • Apr 20 '21 • Edited

Yea, this was my reaction as well; when a simple if isn't enough anymore, higher-order functions is the way to go.

However, I'd add the data as its own argument to make things more convenient:

const validate = validations => subject => validations.every(validation => validation(subject))

const confirmed = validate([ user => user.email_confirmed ])
const allowed = validate([ confirmed, user => user.age > 18  ])

bugb • Apr 23 '21 • Edited

The problem is how do you know what the piece of data that is invalid age or username or something (you need to have additional code). And what if you want to throw custom error message for each case?

Array in JS is also weird (if you dont know the spec of map or using Typescript)

a=[].map(v=>v.v.v.v.v.v) // it is valid

It can cause debuging becomes nightmare!

So I prefer if-else.

MalikKillian • Apr 20 '21

I'd prefer a ternary over the if-else, but changing the tests to a list of functions is excellent. Adding, updating, removing tests becomes dead simple at this point and it's easier to test.

🐤🥇 Jasper de Jager • Apr 20 '21

good example! 😍

Jack • Apr 20 '21

this 👍

Ingo Steinke, web developer • Apr 20 '21 • Edited

Thanks for the inspiring example. Although .some is a useful method, I would never commit or even write code like this, I even doubt it works (in the way I thought it was intended to).

In general, I prefer to write more explicit and verbose code rather than oversimplified stuff that might be misleading when reading to maintain and modify.

Thanks to Anner Visser for pointing out what the code actually does: less magic than I thought was intended. To make the checks run in the last line, you would have had to use validator functions in the lines above (or computed properties, unless you stick to vanilla JS), which makes the code already less elegant, less compact, and more like what I have seen in React projects.

🐤🥇 Jasper de Jager • Apr 20 '21

The code does work, it isn't a real world example though 😉

Lorenzo • Apr 20 '21

Hey, where is the funny joke "we all know unicorns don't vomit"?

In all cases, keep it up!

🐤🥇 Jasper de Jager • Apr 20 '21

Even edited this one especially for you 😋

Lorenzo • Apr 20 '21

🙃

🐤🥇 Jasper de Jager • Apr 20 '21

hehe, that's in the first one, I'll use it from now on 😁

Anner Visser • Apr 20 '21 • Edited

I think your last variable should be called isInvalid :)
(or isValid = !checks.some...)

🐤🥇 Jasper de Jager • Apr 20 '21 • Edited

😘 thanks, fixed it!

Jan Küster • Apr 21 '21

Some is a great tool especially because it skips the for loop. I would only use it in a project with experienced devs, newcomers could be confused. Still commit