Hacker News Reader

Comment by SCLeo | Hacker News Reader

I honestly don't understand why people use packages like this. If I need this functionality, I will simply write my own. Plus, I will never able to find this specific package. I guess PureScript uses this because its author is also the author of rate-map.

View on HN

I’ll give you one: it’s code already written and tested by > 1 person, edge cases already figured out. Saves you time. The gains are small but quickly add up.

This is why lately I’ve been a fan of very extensive standard libraries (like Crystal has) - its like having a huge repository but vetoed by the same team and without any of the package management drawbacks.

> The gains are small but quickly add up.

There are costs to these micro-libraries that outweigh the gains. This code is trivial; there aren’t really edge cases to be worked out.

Also: the way the library handles those edge cases isn't necessarily the way you want. Case in point: rate-map throws exceptions in situations where you might expect it to fail more gracefully.

What gains? That line wouldn't take much resources or time to figure out and test. Now you have yet another dependency that could be injected with bad code in the future...

> it’s code already written and tested by > 1 person, edge cases already figured out.

It is tested? Edge cases figured out? Essentially for this code?:

    return start + val * (end - start);

Sure, if its running in hostile environment, you might need to do those sanity checks for your parameters - but I have hard time imagining such situation. If you actually need to "Map a number in the range of 0-1 to a new value with a given range" in your own code, can't you guarantee that the variables are all numbers? Its your responsibility as a developer to know your code, and the data your code is handling.

> Saves you time.

There is something really wrong if finding a package to do this niche thing is faster and more optimal that just writing out that one line of code.

[C]ode already written and tested by > 1 person, edge cases already figured out wastes time when that person was not you. This costs you time. The losses are small but they add up.

>The gains are small but quickly add up.

Same could also be said for build times not to mention security issues should one of your micro-dependencies be hijacked.

> edge cases already figured out.

Nope, it doesn't guarantee its invariants. This would pass all the tests and yet returns a value out of bounds:

    > s = 1e12
    1000000000000
    > e = 1e-8
    1e-8
    > s + 1.0 * (e - s)
    0

> This is why lately I’ve been a fan of very extensive standard libraries (like Crystal has) - its like having a huge repository but vetoed by the same team and without any of the package management drawbacks.

Having had some involvement in the early days of node, I had imagined there being something like the Python stdlib. When the npm world grew, I thought "oh, that's pretty cool. It's neat how npm can handle multiple versions of the same package."

Now, I'm in absolute agreement with you. There are definitely downsides to a large standard library, but I think the upsides are worth it if that library is maintained.

As usual, everyone here will start their "I'm better than this" comments.

If you've ever used a code dependency, you are a target for malicious code. That's just how it is.

In this case, using small packages like this helps in...

1. Reliability - these packages are typically 100% unit tested

2. Convenience

3. Reduce codebase size. I can't imagine having to copy paste every little small function into a mega utils file.

You should take a look at the trim package and how often hat is downloaded.

There is not even a link to the source code on the npm page for it. I installed it and inspected the source code, but I doubt everyone does this when installing a dependency.

Here's the complete source for anyone curious

``` exports = module.exports = trim;

function trim(str){ return str.replace(/^\s|\s$/g, ''); }

exports.left = function(str){ return str.replace(/^\s/, ''); };

exports.right = function(str){ return str.replace(/\s$/, ''); };

```

That code doesn't match what actually happens. It will only trim a single character. Have asterisks been trimmed in your copy-paste or something?

Ah you're right, the asterisks have been interpreted as italics. Can't edit my comment, sorry

Here's a paste: https://pastebin.com/kBHprdyj

Funnily enough, in my opinion, the JS ecosystem fully embraced the Unix way: have small programs/libs that do only one thing and do it (somewhat) well.

I fear your analogy does not go far enough if you are comparing the JS ecosystem to the UNIX philosophy.

Javascript would offer a library for every single option, variant and logical operator for a UNIX command. Combinatorial explosion will devour the web. It already destroys dev laptops anyways when downloading something via NPM.

No, they do not on the whole do anything well.

Reply on news.ycombinator.com