138 lines
4.1 KiB
Markdown
138 lines
4.1 KiB
Markdown
# SwiftMVI
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**SwiftMVI** is an open-source library of definitions and related extensions for modern swift application development.
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## Overview
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**SwiftMVI** provides the following features:
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- Lightweight & scalable: Wide range of possible implementations from a single reducer to complex feature
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- Able to publish events
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- A simple but very effective API bind your combine publishers to reducers and publishers.
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The goal is a set of protocols for archiving structured data-flow with minimal effort.
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There are some important differences compared to other MVI implementations.
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First of all in SwiftMVI state is a mutable ``ObservableObject``, therefore the reducers are not returns anything not even an effect. The reducers connect to each other using the ``Processing`` protocol and its api. Your existing Combine publishers can be connected using ```.bind``` method and your implemented ``Feature`` can be inserted as A **Publisher** instance. in any process using ``EventReducer``.
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## Installation
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You can use Swift Package Manager to integrate the library by adding the following dependency in your Package.swift file or by adding directly within Xcode:
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```swift
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.Package(url: "https://github.com/xtro/SwiftMVI.git", majorVersion: 1)
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```
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## Usage
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To build a ui feature using the SwiftMVI you define some types and values that model your domain:
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- **MutableState**: A type that describes the state of your UI.
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- **Intent**: A type that represents all of the actions that can happen in your feature, such as user actions, notifications, event sources and more.
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- **IntentReducer**: A function that handle intents and process them over time.
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- **Processing**: Enable processing functionalities in a feature.
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As a basic example, consider a UI that shows a number along with "+" and "−" buttons that increment and decrement the number.
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In here we need to define a type for the feature's state, which consists of an integer for the current count:
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```swift
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import SwiftMVI
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class Feature: ObservableObject, MutableState {
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class State {
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var count = 0
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}
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var state = State()
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}
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```
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We also need to define a type for the feature's intents, there are two intents one for increase and one for decrease:
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```swift
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extension Feature: IntentReducer {
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enum Intent {
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case increment
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case decrement
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}
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}
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```
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And then we implement the reduce method which is responsible for handling the behavior of the feature. In this example for change the state we need to add ``Processing`` protocol and call ``.state``:
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```swift
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extension Feature: IntentReducer, Processing {
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enum Intent { ... }
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func reduce(intent: Intent) {
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switch intent {
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case .increment:
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state {
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$0.count += 1
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}
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case .decrement:
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state {
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$0.count -= 1
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}
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}
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}
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}
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```
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And then finally we define the view that displays the feature, adding as ``StateObject`` or ``ObservedObject`` and call by passing its own ``Intent``:
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```swift
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struct FeatureView: View {
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@StateObject var feature = Feature()
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var body: some View {
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VStack {
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HStack {
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Button("−") { feature(.decrement) }
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Text("\(feature.state.count)")
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Button("+") { feature(.increment) }
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}
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}
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}
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}
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```
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## Topics
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### Reducers
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- ``IntentReducer``
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- ``EffectReducer``
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- ``EventReducer``
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- ``ActionReducer``
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- ``ReactionReducer``
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- ``ImmutableReducer``
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- ``Reducer``
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- ``Binding``
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### Async reducers
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- ``AsyncIntentReducer``
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- ``AsyncEffectReducer``
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- ``AsyncActionReducer``
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- ``AsyncReactionReducer``
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### State
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- ``MutableState``
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### Processing
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- ``ReducerComponent``
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- ``Processing``
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### Components
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- ``ReducerComponent``
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<!--### Usecase feature-->
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<!--- ``UseCaseFeature``-->
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<!--- ``IntentUseCaseFeature``-->
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<!--- ``EffectUseCaseFeature``-->
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<!--### Async usecase feature-->
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<!--- ``AsyncUseCaseFeature``-->
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<!--- ``AsyncEffectUseCaseFeature``-->
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<!--- ``AsyncIntentUseCaseFeature``-->
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