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https://github.com/QuickBirdEng/NonEmptyCollections
A type-safe implementation for collections that cannot be empty. Life is too short for emptiness-checks!
https://github.com/QuickBirdEng/NonEmptyCollections
List: NonEmptyCollections
android collection collections empty immutability input kotlin library list lists map maps non non-empty restrict safety set sets type
Last synced: 9 days ago
JSON representation
A type-safe implementation for collections that cannot be empty. Life is too short for emptiness-checks!
- Host: GitHub
- URL: https://github.com/QuickBirdEng/NonEmptyCollections
- Owner: QuickBirdEng
- License: mit
- Created: 2021-03-17T11:05:31.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2024-05-06T07:25:06.000Z (6 months ago)
- Last Synced: 2024-05-22T11:10:18.634Z (6 months ago)
- Topics: android, collection, collections, empty, immutability, input, kotlin, library, list, lists, map, maps, non, non-empty, restrict, safety, set, sets, type
- Language: Kotlin
- Homepage:
- Size: 111 KB
- Stars: 51
- Watchers: 4
- Forks: 4
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-list - QuickBirdEng/NonEmptyCollections - A type-safe implementation for collections that cannot be empty. Life is too short for emptiness-checks! (Kotlin)
README
# NonEmptyCollections
## Making the world a little more type-safe 🌍🏆
Reduce the need for emptiness checks and reduce unsafe APIs with **NonEmptyCollections**.
You can use `NonEmptyList`, `NonEmptySet` and `NonEmptyMap` to restrict the input of functions to make your code safer and avoid unnecessary runtime exceptions.
For a detailed explanation see our related article [Non-Empty Lists in Kotlin](https://quickbirdstudios.com/blog/non-empty-lists-kotlin).
This is an early version and work in progress. Do not hesitate to give feedback, ideas or improvements via an issue.
# Examples
## Average without exceptions
With the `NonEmptyList` type, we can make sure that at least one element is always a list. If we want to calculate the average of that list, it is impossible to compile a program where an invalid input is passed to our function.
```kotlin
fun NonEmptyList.average() = sum() / size
```
```kotlin
nonEmptyListOf().average() // This does not compile! ❌
nonEmptyListOf(1, 2, 3).average() // This does! ✅
```
## Non-empty Shopping-Cart
Let's imagine an online shop, where you can put articles into a shopping cart. If you have some articles in the shopping cart, you should be able to share the articles with your friends, save them for later on a wish list or directly buy them. But these three features just make sense if the shopping cart is not empty. Wouldn't it be cool to already prevent at compile-time that somebody tries these features with an empty set of articles?
```kotlin
sealed class ShoppingCart {
object Empty : ShoppingCart()
data class Filled(
val articles: NonEmptySet
) : ShoppingCart() {
fun buy(paymentType: PaymentType) = articles.buy(paymentType)
fun share() = articles.share()
fun saveTo(wishList: WishList) = articles.saveTo(wishList)
}
}
fun NonEmptyCollection.buy(paymentType: PaymentType) { 💸 }
fun NonEmptyCollection.share() { 💬 }
fun NonEmptyCollection.saveTo(wishList: WishList) { 💾 }
```
The devs, who implement `buy`, `share` and `saveTo` don't have to handle the empty case. The consumers of these APIs don't have to think of exception handling, because they are forced by the compiler to provide a valid input. We would say, that's a win-win situation 🏆.
# 🏃 Library Setup
## 1. Add the repository
`build.gradle.kts`
```kotlin
allprojects {
repositories {
...
maven { url = uri("https://jitpack.io") }
}
}
```
## 2. Add the dependency
`build.gradle.kts`
```kotlin
dependencies {
...
implementation("com.github.quickbirdstudios.NonEmptyCollections:NonEmptyCollections:1.1.0")
}
```
# 👤 Author
This Kotlin library is created with ❤️ by [QuickBird Studios](https://quickbirdstudios.com/).
# ❤️ Contributing
Open an issue if you need help, if you found a bug, or if you want to discuss a feature request.
Open a PR if you want to make changes to NonEmptyCollections.
# 📃 License
NonEmptyCollections is released under an MIT license. See [License](LICENSE) for more information.