HyperApp is a 1kb JavaScript library for building modern UI applications.
npm i hyperapp
CommonJS
const { h, app } = require("hyperapp")
ES6
import { h, app } from "hyperapp"
With Browserify.
browserify -t hyperxify -g uglifyify index.js | uglifyjs > bundle.js
HyperApp is also distributed as a minified file, hosted on a CDN.
<script src="https://unpkg.com/hyperapp/dist/hyperapp.js"></script>
For a more thorough introduction and advanced usage see the HyperApp User Guide.
app({
model: 0,
update: {
add: model => model + 1,
sub: model => model - 1
},
view: (model, actions) =>
<div>
<button onclick={actions.add}>+</button>
<h1>{model}</h1>
<button onclick={actions.sub} disabled={model <= 0}>-</button>
</div>
})
app({
model: "",
update: {
text: (_, value) => value
},
view: (model, actions) =>
<div>
<h1>Hi{model ? " " + model : ""}.</h1>
<input oninput={e => actions.text(e.target.value)} />
</div>
})
const model = {
dragging: false,
position: {
x: 0, y: 0, offsetX: 0, offsetY: 0
}
}
const view = (model, actions) =>
<div
onmousedown={e => actions.drag({
position: {
x: e.pageX, y: e.pageY, offsetX: e.offsetX, offsetY: e.offsetY
}
})}
style={{
userSelect: "none",
cursor: "move",
position: "absolute",
padding: "10px",
left: `${model.position.x - model.position.offsetX}px`,
top: `${model.position.y - model.position.offsetY}px`,
backgroundColor: model.dragging ? "gold" : "deepskyblue"
}}
>Drag Me!
</div>
const update = {
drop: model => ({ dragging: false }),
drag: (model, { position }) => ({ dragging: true, position }),
move: (model, { x, y }) => model.dragging
? ({ position: { ...model.position, x, y } })
: model
}
const subscriptions = [
(_, actions) => addEventListener("mouseup", actions.drop),
(_, actions) => addEventListener("mousemove", e =>
actions.move({ x: e.pageX, y: e.pageY }))
]
app({ model, view, update, subscriptions })
const FilterInfo = { All: 0, Todo: 1, Done: 2 }
app({
model: {
todos: [],
filter: FilterInfo.All,
input: "",
placeholder: "Add new todo!"
},
view: (model, msg) =>
<div>
<h1>Todo</h1>
<p>
Show: {Object.keys(FilterInfo)
.filter(key => FilterInfo[key] !== model.filter)
.map(key =>
<span><a data-no-routing href="#" onclick={_ => msg.filter({
value: FilterInfo[key]
})}>{key}</a> </span>
)}
</p>
<p><ul>
{model.todos
.filter(t =>
model.filter === FilterInfo.Done
? t.done :
model.filter === FilterInfo.Todo
? !t.done :
model.filter === FilterInfo.All)
.map(t =>
<li style={{
color: t.done ? "gray" : "black",
textDecoration: t.done ? "line-through" : "none"
}}
onclick={e => msg.toggle({
value: t.done,
id: t.id
})}>{t.value}
</li>)}
</ul></p>
<p>
<input
type="text"
onkeyup={e => e.keyCode === 13 ? msg.add() : ""}
oninput={e => msg.input({ value: e.target.value })}
value={model.input}
placeholder={model.placeholder}
/>{" "}
<button onclick={msg.add}>add</button>
</p>
</div>,
update: {
add: model => ({
input: "",
todos: model.todos.concat({
done: false,
value: model.input,
id: model.todos.length + 1
})
}),
toggle: (model, { id, value }) => ({
todos: model.todos.map(t =>
id === t.id
? Object.assign({}, t, { done: !value })
: t)
}),
input: (model, { value }) => ({ input: value }),
filter: (model, { value }) => ({ filter: value })
}
})
Import the h function and include the jsx pragma, in any order.
import { h, app } from "hyperapp"
/** @jsx h */
app({
model: "Hi.",
view: model => <h1>{model}</h1>
})
Or, add it to your .babelrc configuration.
{
"plugins": [
["transform-react-jsx", { "pragma": "h" }]
]
}
To use HyperApp without jsx, import the html function instead.
const { html, app } = require("hyperapp")
app({
model: "Hi.",
view: model => html`<h1>${model}</h1>`
})
html is a Hyperx-based template function.
Use app to start the app.
app({
model,
update,
view,
effects,
subscriptions,
root,
router
})
A primitive type, array or object that represents the state of your application. HyperApp applications use a single model architecture.
An object composed of functions often called reducers. A reducer describes how to derive the next model from the current model.
const update = {
increment: model => model + 1,
decrement: model => model - 1
}
Reducers can return an entirely new model or part of a model. If a reducer returns part of a model, it will be merged with the current model.
Reducers can be triggered inside a view, effect or subscription.
Reducers have the signature (model, data, params):
model is the current model.data is the data sent to the reducer.When using the Router, the view receives additionally
params an object with the matched route parameters.A function that returns an HTML element using jsx or the html function.
A view has the signature (model, actions):
To use actions:
actions.action(data)
data is any data you want to send to action.action is the name of the reducer or effect.app({
model: true,
view: (model, actions) => <button onclick={actions.toggle}>{model+""}</button>,
update: {
toggle: model => !model
}
})
Functions that can be attached to your virtual HTML nodes to access their real DOM elements.
HTMLElement)HTMLElement)HTMLElement)app({
view: _ => <div oncreate={e => console.log(e)}>Hi.</div>
})
const repaint = (canvas, model) => {
const context = canvas.getContext("2d")
context.fillStyle = "white"
context.fillRect(0, 0, canvas.width, canvas.height)
context.beginPath()
context.arc(model.x, model.y, 50, 0, 2 * Math.PI)
context.stroke()
}
app({
model: { x: 0, y: 0 },
view: model => <canvas
width="600"
height="300"
onupdate={e => repaint(e, model)} />,
update: {
move: (model) => ({ x: model.x + 1, y: model.y + 1 })
},
subscriptions: [
(_, actions) => setInterval(_ => actions.move(), 10)
]
})
Actions that cause side effects and can be asynchronous, like writing to a database, or sending requests to servers.
Effects have the following signature: (model, actions, data, error).
model is the current model.actions is an object used to trigger reducers and effects.data is the data sent to the effect.error is a function you may call to throw an error.const wait = time => new Promise(resolve => setTimeout(_ => resolve(), time))
const model = {
counter: 0,
waiting: false
}
const view = (model, actions) =>
<button
onclick={actions.waitThenAdd}
disabled={model.waiting}>{model.counter}
</button>
const update = {
add: model => ({ counter: model.counter + 1 }),
toggle: model => ({ waiting: !model.waiting})
}
const effects = {
waitThenAdd: (model, actions) => {
actions.toggle()
wait(1000).then(actions.add).then(actions.toggle)
}
}
app({ model, view, update, effects })
Subscriptions are functions scheduled to run only once when the DOM is ready. Use a subscription to register global events, open a socket connection, attached mouse or keyboard event listeners, etc.
A subscription has the signature (model, actions, error).
app({
model: { x: 0, y: 0 },
update: {
move: (_, { x, y }) => ({ x, y })
},
view: model => <h1>{model.x}, {model.y}</h1>,
subscriptions: [
(_, actions) => addEventListener("mousemove", e => actions.move({
x: e.clientX,
y: e.clientY
}))
]
})
Function handlers that can be used to inspect your application, implement middleware, loggers, etc. There are three: onUpdate, onAction, and onError.
Called when the model changes. Signature: (lastModel, newModel, data).
Called when an action (reducer or effect) is triggered. Signature: (name, data).
Called when you use the error function inside a subscription or effect. If you don't use this hook, the default behavior is to throw. Signature: (err).
app({
model: true,
view: (model, actions) =>
<div>
<button onclick={actions.doSomething}>Log</button>
<button onclick={actions.boom}>Error</button>
</div>,
update: {
doSomething: model => !model,
},
effects: {
boom: (model, actions, data, err) => setTimeout(_ => err(Error("BOOM")), 1000)
},
hooks: {
onError: e =>
console.log("[Error] %c%s", "color: red", e),
onAction: name =>
console.log("[Action] %c%s", "color: blue", name),
onUpdate: (last, model) =>
console.log("[Update] %c%s -> %c%s", "color: gray", last, "color: blue", model)
}
})
The HTML element container of your application. If none is given, a div element is appended to document.body and used as the container.
HyperApp provides a router out of the box.
import { h, app, router } from "hyperapp"
app({ view, router })
When using the router, the view must be an object that consists of routes, each with a corresponding view function.
app({
view: {
"/": (model, actions) => {},
"/about": (model, actions) => {},
"/:key": (model, actions, params) => {}
}
})
const Anchor = ({ href }) => <h1><a href={"/" + href}>{href}</a></h1>
app({
view: {
"/": _ => <Anchor href={Math.floor(Math.random() * 999)}></Anchor>,
"/:key": (model, actions, { key }) =>
<div>
<h1>{key}</h1>
<a href="/">Back</a>
</div>
},
router
})
/ matches the index route or when no other route matches.
/:key matches a route using the regular expression [A-Za-z0-9]+. The matched key is passed to the route's view function via params.
The router path syntax is loosely based in the same syntax used in Express.
A special action available when using the Router. Use setLocation(path) to update the location.pathname. If the path matches an existing route, the corresponding view will be rendered.
const Page = ({ title, target, onclick }) =>
<div>
<h1>{title}</h1>
<button onclick={onclick}>{target}</button>
</div>
app({
router,
view: {
"/": (model, actions) =>
<Page
title="Home"
target="About"
onclick={_ => actions.setLocation("/about")}>
</Page>
,
"/about": (model, actions) =>
<Page
title="About"
target="Home"
onclick={_ => actions.setLocation("/")}>
</Page>
}
})
HyperApp intercepts all <a href="/path">...</a> clicks and calls action.setLocation("/path") for convenience. External links and links that begin with a # character are not intercepted.
app({
view: {
"/": (model, msg) =>
<div>
<h1>Home</h1>
<a href="/about">About</a>
</div>
,
"/about": (model, msg) =>
<div>
<h1>About</h1>
<a href="/">Home</a>
</div>
}
})
Add a custom data-no-routing attribute to anchor elements that should be handled differently.
<a data-no-routing>Not a route</a>
FAQs
The tiny framework for building hypertext applications.
The npm package hyperapp receives a total of 5,742 weekly downloads. As such, hyperapp popularity was classified as popular.
We found that hyperapp demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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