🪨 @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
- register components to the dom
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
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>${count}</span>`
- use.computed
create a signal that is derived from other signals
const count = use.signal(2)
const tripled = use.computed(() => count.value * 3)
console.log(tripled.value)
- use.op
create an OpSignal in a loading/error/ready state, and it can hold a result value
const count = use.op()
count.run(async() => fetchCount("/count"))
- use.flatstate
create a reactive object (inspired by mobx and snapstate)
const state = use.flatstate({count: 0})
const increment = () => state.count++
- use.setup
perform setup/cleanup on dom connected/disconnected
use.setup(() => {
const interval = setInterval(increment, 1000)
return () => clearInterval(interval)
})
- use.prepare
initialize a value once
const random_number = use.prepare(() => Math.random())
- use.context
access to your app's context, for whatever reason
await use.context.flat.wait
await use.context.tower.wait
by default, context has theme
, tower
, and flat
, but you specify your own context in prepare_frontend
, so you can put any app-level state in there that you might want
special use
access
- use.element ~ carbon, oxygen, obsidian
access the underlying html element
use.element.querySelector("p")
- use.shadow ~ carbon, obsidian
access to the shadow root
use.shadow.querySelector("slot")
- use.attrs ~ carbon, oxygen
declare accessors for html attributes
const attrs = use.attrs({
start: Number,
label: String,
["data-active"]: Boolean,
})
set them like normal js properties
attrs.start = 123
attrs.label = "hello"
attrs["data-active"] = true
get them like normal js properties
console.log(attrs.start)
console.log(attrs.label)
console.log(attrs["data-active"])
components rerender when any attributes change from outside
🔮 advanced stuff
gold and silver elements
export const MyGold = component(context => class extends GoldElement {
static styles = css`span {color: blue}`
#state = context.flat.state({
count: 0,
})
render() {
return html`
<span>${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 classSilverElement
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)
console.log(greeting.value)
- track — react when signals change
tower.track(() => console.log("doubled", count.value * 2))
count.value = 2
- 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)
await json.run(async() => {
const data = await fetch_remote_data()
return JSON.parse(data)
})
console.log(json.ready)
console.log(json.payload)
- computed — signal derived from other signals
count.value = 1
const tripled = tower.computed(() => count.value * 3)
console.log(tripled.value)
- wait — for debounced tracking
const tripled = tower.computed(() => count.value * 3)
console.log(tripled.value)
count.value = 10
console.log(tripled.value)
await tower.wait
console.log(tripled.value)
🥞 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()
- make a flat state object
const state = flat.state({count: 0})
- setup a reaction
flat.reaction(() => console.log(state.count))
state.count++
- 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)
await flat.wait
console.log(state.amount)
- you can stop a reaction
const stop = flat.reaction(() => console.log(state.count))
stop()
- clear all reactions on a flatstate 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
flatstate integration with frontend elements
💫 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()
Op.error("a fail occurred")
Op.ready(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
function example(op: Op.Any<number>) {
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)
}
🪈 pipe
- pipe data through a series of functions
- maybe you've done silly nesting like this:
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"
Pipe.with(elements)
.to(requirement.provide(context))
.to(apply.css(theme))
.to(apply.flat(flat))
.to(apply.signals(signals))
.to(register_to_dom)