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@benev/slate
@benev/slate/x/index.js

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Readme

🪨 `@benev/slate`

🚧 prerelease wip under constructon subject to change

frontend ui framework, built on lit
wonderful web components
versatile views
hipster hooks syntax
satisfying state management
useful utilities
top-tier typescript typings

👷 quick start

install slate
```
npm i @benev/slate
```

prepare your app's frontend and context

import {prepare_frontend, Context} from "@benev/slate"

export const {carbon, oxygen, obsidian, quartz} = (
  prepare_frontend(new class extends Context {
    theme = css`
      * {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
      }
    `
  })
)

import html and css template functions
```
import {html, css} from "@benev/slate"
```

⚙️ components

you can create custom html elements that work in plain html or any web framework.

carbon — shadow-dom component

const styles = css`span {color: yellow}`

export const MyCarbon = carbon({styles}, use => {
  const count = use.signal(0)
  const increment = () => count.value++

  return html`
    <span>${count}</span>
    <button @click=${increment}>increment</button>
  `
})

oxygen — light-dom component

export const MyOxygen = oxygen(use => {
  const count = use.signal(0)
  const increment = () => count.value++

  return html`
    <span>${count}</span>
    <button @click=${increment}>increment</button>
  `
})

using your components

import {register_to_dom} from "@benev/slate"

register_to_dom({
  MyCarbon,
  MyOxygen,
})

now use your components via html

<section>
  <my-carbon></my-carbon>
  <my-oxygen></my-oxygen>
</section>

🖼️ views

views are just like components, but are not registered to the dom as custom html elements.
instead, they are used via javascript.
you import them, and inject them into your lit-html templates.
they accept js parameters called props, and are fully typescript-typed.

obsidian — shadow-dom view

const styles = css`span {color: yellow}`

export const MyObsidian = obsidian({styles}, use => (start: number) => {
  const count = use.signal(start)
  const increment = () => count.value++

  return html`
    <span>${count}</span>
    <button @click=${increment}>increment</button>
  `
})

auto_exportparts is enabled by default.
- auto exportparts is an obsidian feature that makes it bearable to use the shadow dom extensively.
- if auto_exportparts is enabled, and you provide the view a part attribute, then it will automatically re-export all internal parts, using the part as a prefix.
- thus, parts can bubble up: each auto_exportparts shadow boundary adds a new hyphenated prefix, so you can do css like ::part(search-input-icon).

quartz — light-dom view

export const MyQuartz = quartz(use => (start: number) => {
  const count = use.signal(start)
  const increment = () => count.value++

  return html`
    <span>${count}</span>
    <button @click=${increment}>increment</button>
  `
})

using your views

use a quartz view
```
html`<div>${MyQuartz(123)}</div>`
```
- quartz views are beautifully simple
- without any shadow-dom, they have no stylesheet, and without a wrapping element, they have no attributes

use an obsidian view

html`<div>${MyObsidian([123])}</div>`

obsidian views need their props wrapped in an array
when rendered, obsidian views are wrapped in a <obsidian-view> component, which is where the shadow root is attached

obsidian views will accept a settings object

html`
  <div>
    ${MyObsidian([123], {
      content: html`<p>slotted content</p>`,
      auto_exportparts: true,
      attrs: {
        part: "cool",
        "data-whatever": true,
      },
    })}
  </div>
`

🪝 `use` hooks

universal hooks for all views and components

use.state
works like react useState hook

const [count, setCount] = use.state(0)
const increment = () => setCount(count + 1)

use.signal
create a reactive container for a value (inspired by preact signals)
```
const count = use.signal(0)
const increment = () => count.value++
```
you can directly inject the whole signal into html
```
html`<span>${count}</span>`
```

use.computed create a signal that is derived from other signals

const count = use.signal(2)
const tripled = use.computed(() => count.value * 3)
console.log(tripled.value) //> 6

use.op
create an OpSignal in a loading/error/ready state, and it can hold a result value
```
const count = use.op()
count.run(async() => fetchCount("/count"))
```

use.flatstate
create a reactive object (inspired by mobx and snapstate)

const state = use.flatstate({count: 0})
const increment = () => state.count++

use.setup
perform setup/cleanup on dom connected/disconnected

use.setup(() => {
  const interval = setInterval(increment, 1000)
  return () => clearInterval(interval)
})

use.prepare
initialize a value once

const random_number = use.prepare(() => Math.random())

use.init
perform a setup/cleanup, but also return a value

const scene = use.init(() => {

  // called whenever dom is connected
  const scene = setup_3d_scene_for_example()

  return [
    canvas, // value returned
    () => scene.cleanup(), // cleanup called on dom disconnect
  ]
})

use.context
access to your app's context, for whatever reason
```
// wait for all flatstate reactions to complete
await use.context.flat.wait

// wait for all signal tower reactons to complete
await use.context.tower.wait
```
by default, context has theme, tower, and flat, but you specify your own context in prepare_frontend, so you can put any app-level state in there that you might want

special `use` access

use.element ~ carbon, oxygen, obsidian
access the underlying html element
```
use.element.querySelector("p")
```
use.shadow ~ carbon, obsidian
access to the shadow root
```
use.shadow.querySelector("slot")
```

use.attrs ~ carbon, oxygen
declare accessors for html attributes

const attrs = use.attrs({
  start: Number,
  label: String,
  ["data-active"]: Boolean,
})

set them like normal js properties

attrs.start = 123
attrs.label = "hello"
attrs["data-active"] = true

get them like normal js properties

console.log(attrs.start) // 123
console.log(attrs.label) // "hello"
console.log(attrs["data-active"]) // true

components rerender when any attributes change from outside

🔮 advanced stuff

gold and silver elements

export const MyGold = component(context => class extends GoldElement {
  static styles = css`span {color: blue}`

  #state = context.flat.state({
    count: 0,
  })

  render() {
    return html`
      <span>${this.#state.count}</span>
      <button @click=${() => this.#state.count++}>gold</button>
    `
  }
})

non-hooks class-based LitElement-alternative components
GoldElement is a shadow-dom component base class
SilverElement is a light-dom component base class
these are used as primitives underlying carbon/oxygen components
they do not have context, theme, or any state management reactivity applied
- you can apply those with the mixins found by importing mixins
- you can use Attributes.base(this as BaseElement, {label: String}) to create attribute accessors
- you can wrap your GoldElement/SilverElement in component from prepare_frontend to mixin the theme and state management reactivity

`prepare_frontend` vs `deferred_frontend`

prepare_frontend "bakes" your app context into the component and view functions at import-time, "before" your components and views are defined. this makes your developer experience simple and pleasant for most cases.
however, if you want to accept the context object later for some reason, this can create a bit of an awkward chicken-vs-egg timing situation.
deferred_frontend is an alternative designed to solve this problem by deferring the passing of context to each individual component and view.
deferred makes your experience more cumbersome, because you have to pass the context into every view before you can use them. deferred_frontend gives you a provide function which makes it easy to pass context to a group of views for that purpose.
you might be better of using prepare_frontend and modifying your context at runtime, but before you register_to_dom your components
- eg, you can set context.theme at runtime before register_to_dom

🛠️ standalone utilities

if you're using slate's frontend components and views, you'll probably be using these utilities via the use hooks, which will provide a better developer experience.

however, the following utilities are little libraries in their own right, and can be used in a standalone capacity.

🛎️ signals

signals are a simple form of state management.

this implementation is inspired by preact signals.

signal tower
```
import {SignalTower} from "@benev/slate"

const tower = new SignalTower()
```
- signal towers are completely separated from one another
- you probably only want one in your app, except for special testing situations where isolated signal contexts may be desirable
- you could export this tower from a module that you import all over your app

signals — they hold values

const count = tower.signal(0)
const greeting = tower.signal("hello")

count.value++
greeting.value = "bonjour"

console.log(count.value) //> 1
console.log(greeting.value) //> "bonjour"

track — react when signals change

tower.track(() => console.log("doubled", count.value * 2))
//> doubled 2

count.value = 2
//> doubled 4

html templating — you can omit .value
```
html`<p>count is ${count}</p>`
```

op signal — to represent async operations

const json = tower.op<MyJson>()

console.log(json.loading) //> true

await json.run(async() => {
  const data = await fetch_remote_data()
  return JSON.parse(data)
})

console.log(json.ready) //> true
console.log(json.payload) //> {"your": "json data"}

computed — signal derived from other signals

count.value = 1

const tripled = tower.computed(() => count.value * 3)

console.log(tripled.value) //> 3

wait — for debounced tracking

const tripled = tower.computed(() => count.value * 3)
console.log(tripled.value) //> 3

count.value = 10
console.log(tripled.value) //> 3 (too soon!)

await tower.wait
console.log(tripled.value) //> 30 (there we go)

🥞 flatstate

flatstate help you create state objects and react when properties change.

flatstate is inspired by mobx and snapstate, but designed to be super simple: flatstate only works on flat state objects, only the direct properties of state objects are tracked for reactivity.

flatstate basics

create a flatstate tracking context

import {Flat} from "@benev/slate"

const flat = new Flat()
  // what happens in this flat, stays in this flat.
  // you probably only want one for your whole app.

make a flat state object
```
const state = flat.state({count: 0})
```
setup a reaction
```
flat.reaction(() => console.log(state.count))
  //> 0

state.count++
  //> 1
```
- flatstate records which state properties your reaction reads
- flatstate calls your reaction whenever those specific properties change
- your reaction can listen to more than one state object

flatstate details

reactions are debounced -- so you may have to wait to see state changes

const flat = new Flat()
const state = flat.state({amount: 100})

state.amount = 101
console.log(state.amount) //> 100 (old value)

await flat.wait
console.log(state.amount) //> 101 (now it's ready)

you can stop a reaction

const stop = flat.reaction(() => console.log(state.count))

stop() // end this particular reaction

clear all reactions on a flatstate instance

// clear all reactions on this flat instance
flat.clear()

flatstate reactions

so first, there's a simple one-function reaction:
```
flat.reaction(() => console.log(state.count))
```
- flatstate immediately runs the function, and records which properties it reads
- then, anytime one of those properties changes, it runs your function again
you can also do a two-function reaction:
```
flat.reaction(
  () => ({count: state.count}),
  ({count}) => console.log(count),
)
```
- now there's a separation between your "collector" and your "responder"
- the collector "passes" relevant data to the responder function
- flatstate calls the responder whenever that data changes
there's also something called "deepReaction"
```
flat.deepReaction(() => console.log(state.count))
```
- it's the same as "reaction", but it has "discovery" enabled
- discovery means the collector is checked again for every responder call
- it's less efficient, but allows you to respond to deeply nested recursive structures
there's also .auto and .manual reactions
- these allow you to set options like discovery and debounce (you can turn off the debouncer)
- but that's bigbrain stuff that you'll have to read the sourcecode about

flatstate advanced

multiple flatstate instances are totally isolated from each other
```
const flat1 = new Flat()
const flat2 = new Flat()
```

create readonly access to a state object

const state = flat.state({count: 0})
const rstate = Flat.readonly(state)

state.count = 1
await flat.wait
console.log(rstate.count) //> 1

rstate.count = 2 // !! ReadonlyError !!

btw, you can use readonly on anything, not just flatstate

flatstate integration with frontend elements

let your components rerender on flat state changes

import {apply} from "@benev/slate"

const MyElement2 = mixin.flat(flat)(MyElement)
  // can also be a class decorator

const elements2 = apply.flat(flat)(elements)

this works on any BaseElement, which includes LitElement, GoldElement, SilverElement, carbon, and oxygen

💫 op

utility for ui loading/error/ready states.

useful for implementing async operations that involve loading indicators.

you get a better dev-experience if you use ops via signals, but here is the documentation for plain ops on their own, without signals.

create some ops

import {Op} from "@benev/slate"

Op.loading()
  //= {mode: "loading"}

Op.error("a fail occurred")
  //= {mode: "error", reason: "a fail occurred"}

Op.ready(123)
  //= {mode: "ready", payload: 123}

you can run an async operation and keep things synchronized

let my_op = Op.loading()

await Op.run(op => my_op = op, async() => {
  await nap(1000)
  return 123
})

you can create op signals that have op functionality built in

const count = use.op()

count.run(async() => {
  await sleep(1000)
  return 123
})

functions to interrogate an op

  //        type for op in any mode
  //                 v
function example(op: Op.Any<number>) {

  // branching based on the op's mode
  Op.select(op, {
    loading: () => console.log("op is loading"),
    error: reason => console.log("op is error", reason),
    ready: payload => console.log("op is ready", payload)
  })

  const payload = Op.payload(op)
    // if the mode=ready, return the payload
    // otherwise, return undefined
}

🪈 pipe

pipe data through a series of functions

maybe you've done silly nesting like this:

// bad
register_to_dom(
  apply.signals(signals)(
    apply.flat(flat)(
      apply.css(theme)(
        requirement.provide(context)(elements)
      )
    )
  )
)

now you can do this instead:

import {Pipe} from "@benev/slate"

// good
Pipe.with(elements)
  .to(requirement.provide(context))
  .to(apply.css(theme))
  .to(apply.flat(flat))
  .to(apply.signals(signals))
  .to(register_to_dom)

@benev/slate