londek / reactea

Rather simple Bubble Tea companion for handling hierarchy and support for lifting state up 🚀

Reactea

Rather simple Bubbletea companion for handling hierarchy, support for lifting state up. and responsive rendering
It Reactifies Bubbletea philosophy and makes it especially easy to work with in bigger projects.

For me, personally - It's a must in project with multiple pages and component communication

Check our quickstart right here or other examples here!

Installation

go get -u github.com/londek/reactea

General info

The goal is to create components that are

• dimensions-aware (especially unify all setSize conventions)
• move on from raw strings to higher level of abstraction
• propful
• easy to lift the state up
• able to communicate with parent without importing it (I spent too many hours solving import cycles hehe)
• easier to code
• all of that without code duplication

The extreme performance is not main goal of this package, because either way Bubbletea
refresh rate is only 60hz and 50 allocations in entire runtime won't really hurt anyone.
Most info is currently in source code so I suggest checking it out

Always return reactea.Destroy instead of tea.Quit in order to follow our convention

As of now Go doesn't support type aliases for generics, so Renderer[TProps] has to be explicitly casted.

Quickstart

Reactea unlike Bubbletea implements two-way communication, very React-like communication.
If you have experience with React you are gonna love Reactea straight away!

While it may look in following tutorial that Reactea overcomplicates things, trust me, for major projects it's a lifesaver!

In this tutorial we are going to make application that consists of 2 pages.

• The /input (aka index, in reactea default) page for inputting your name
• The /displayname page for displaying your name

Lifecycle

More detailed docs about component lifecycle can be found here, we are only gonna go through basics.

Reactea component lifecycle consists of 6 methods (while Bubbletea only 3)

Method	Purpose
Init(TProps) tea.Cmd	It's called first. All critical stuff should happen here. It also supports IO through tea.Cmd
Update(tea.Msg) tea.Cmd	It reacts to Bubbletea IO and updates state accordingly
AfterUpdate() tea.Cmd	It's called after root component finishes Update(). Components should queue themselves
Render(int, int) string	It renders the UI. The two arguments are width and height, they should be calculated by parent
Destroy()	It's called whenever Component is about to end it's lifecycle. Please note that it's parent's responsibility to call Destroy()
UpdateProps(TProps)	Derives state from given properties. Usually called from Init()

Your first application should consist only of Update and Render, all other methods will be implemented by reactea.BasicComponent and reactea.BasicPropfulComponent.

Let's get to work!

The /input page

/pages/input/input.go

type Component struct {
    reactea.BasicComponent                // It implements AfterUpdate() for us, so we don't have to care!
    reactea.BasicPropfulComponent[Props]  // It implements props backend - UpdateProps() and Props()

    textinput textinput.Model             // Input for inputting name
}

type Props struct {
    SetText func(string)  // SetText function for lifting state up
}

func New() *Component {
    return &Component{textinput: textinput.New()}
}

func (c *Component) Init(props Props) tea.Cmd {
    // Always derive props in Init()! If you are not replacing Init(),
    // reactea.BasicPropfulComponent will take care of it
    c.UpdateProps(props)
    
    return c.textinput.Focus()
}

func (c *Component) Update(msg tea.Msg) tea.Cmd {
    switch msg := msg.(type) {
    case tea.KeyMsg:
        if msg.Type == tea.KeyEnter {
            // Lifted state power! Woohooo
            c.Props().SetText(c.textinput.Value())

            // Navigate to displayname, please
            reactea.SetRoute("/displayname")
            return nil
        }
    }

    var cmd tea.Cmd
    c.textinput, cmd = c.textinput.Update(msg)
    return cmd
}

// Here we are not using width and height, but you can!
func (c *Component) Render(rc *render.Context) {
    rc.Add(render.Paragraph("Enter your name: " + c.textinput.View()))
    rc.Add(render.Paragraph("And press [ Enter ]"))
}

The /displayname page

/pages/displayname/displayname.go

import (
 "fmt"
)

// Our prop(s) is a string itself!
type Props = string

// Stateless components?!?!
func Renderer(text Props, width, height int) string {
    return fmt.Sprintf("OMG! Hello %s!", text)
}

Main component

/app/app.go

type Component struct {
    reactea.BasicComponent                          // It implements AfterUpdate()
    reactea.BasicPropfulComponent[reactea.NoProps]  // It implements props backend - UpdateProps() and Props()

    mainRouter reactea.Component[router.Props]      // Our router

    text string // The name
}

func New() *Component {
    return &Component{
        mainRouter: router.New(),
    }
}

func (c *Component) Init(reactea.NoProps) tea.Cmd {
    // Does it remind you of something? react-router!
    return c.mainRouter.Init(map[string]router.RouteInitializer{
        "default": func(router.Params) (reactea.SomeComponent, tea.Cmd) {
            component := input.New()

            return component, component.Init(input.Props{
                SetText: c.setText, // Can also use "lambdas" (function can be created here)
            })
        },
        "/displayname": func(router.Params) (reactea.SomeComponent, tea.Cmd) {
            // RouteInitializer requires SomeComponent so we have to convert
            // Stateless component (renderer) to SomeComponent
            component := reactea.Componentify[string](displayname.Renderer)

            return component, component.Init(c.text)
        },
    })
}

func (c *Component) Update(msg tea.Msg) tea.Cmd {
    switch msg := msg.(type) {
    case tea.KeyMsg:
        // ctrl+c support 
        if msg.String() == "ctrl+c" {
            return reactea.Destroy
        }
    }

    return c.mainRouter.Update(msg)
}

func (c *Component) Render(width, height int) string {
    return c.mainRouter.Render(width, height)
}

func (c *Component) setText(text string) {
    c.text = text
}

Main

main.go

// reactea.NewProgram initializes program with
// "translation layer", so Reactea components work
program := reactea.NewProgram(app.New())

if _, err := program.Run(); err != nil {
    panic(err)
}

Component lifecycle

Reactea component lifecycle consists of 6 methods (while Bubbletea only 3)

Method	Purpose
Init(TProps) tea.Cmd	It's called first. All critical stuff should happen here. It also supports IO through tea.Cmd
Update(tea.Msg) tea.Cmd	It reacts to Bubbletea IO and updates state accordingly
AfterUpdate() tea.Cmd	It's called after root component finishes Update(). Components should queue themselves
Render(int, int) string	It renders the UI. The two arguments are width and height, they should be calculated by parent
Destroy()	It's called whenever Component is about to end it's lifecycle. Please note that it's parent's responsibility to call Destroy()
UpdateProps(TProps)	Derives state from given properties. Usually called from Init()

Reactea takes pointer approach for components making state modifiable in any lifecycle method
There are also 2 additional lifecycle methods: AfterUpdate() and UpdateProps()

AfterUpdate()

AfterUpdate() is the only lifecycle method that is not controlled by parent. It's called right after root component finishes Update(). Components should queue itself with reactea.AfterUpdate(component) in Update()

UpdateProps()

UpdateProps() is a lifecycle method that derives state from props, It can happen anytime during lifecycle. Usually called by Init()

Notes

Update() IS NOT guaranteed to be called on first-run, Init() for most part is, and critical logic should be there

Lifecycle is (almost, see AfterUpdate()) fully controlled by parent component making graph above fully theoretical and possibly invalid for third-party components

Stateless components

Stateless components are represented by following function types

	Renderer[TProps any]	ProplessRenderer	DumbRenderer
Properties	✅	❌	❌
Dimensions	✅	✅	❌
Arguments	TProps, int, int	int, int	❌

There are many utility functions for transforming stateless into stateful components or for rendering any component without knowing its type (reactea.RenderAny)

Routes API

Routes API allows developers for easy development of multi-page apps. They are kind of substitute for window.Location inside Bubbletea

reactea.CurrentRoute() Route

Returns current route

reactea.LastRoute() Route

Returns last route

reactea.WasRouteChanged() bool

returns LastRoute() != CurrentRoute()

Reactea Routes now support params

Params have been introduced in order to allow routes like: /teams/123/player/4

Params have to follow regex ^:.*$
^ being beginning of current path level (/^level/)
$being end of current path level (/level$/)

Note that params support wildcards with single :, like /teams/:/player. /teams/123/player, /teams/456/player etc will be matched no matter what and param will be ignored in param map.

Router Component

Router Component is basic implementation of how routing could look in your application. It doesn't support wildcards yet or relative pathing. All data is provided from within props

router.Props

router.Props is a map of route initializers keyed by routes

What is RouteInitializer?

RouteInitializer is function that initializes the current route component