woby
v0.58.7
Published
A high-performance framework with fine-grained observable/signal-based reactivity for building rich applications.
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Woby, a twin project of Voby
A high-performance framework with fine-grained observable-based reactivity for building rich applications.
Features
This works similarly to Solid, but without a custom Babel transform and with a different API.
- No VDOM: there's no VDOM overhead, the framework deals with raw DOM nodes directly.
- No stale closures: functions are always executed afresh, no need to worry about previous potential executions of the current function, ever.
- No rules of hooks: hooks are just regular functions, which you can nest indefinitely, call conditionally, use outside components, whatever you want.
- No dependencies arrays: the framework is able to detect what depends on what else automatically, no need to specify dependencies manually.
- No props diffing: updates are fine grained, there's no props diffing, whenever an attribute/property/class/handler/etc. should be updated it's updated directly and immediately.
- No key prop: you can just map over arrays, or use the
For
component with an array of unique values, no need to specify keys explicitly. - No Babel: there's no need to use Babel with this framework, it works with plain old JS (plus JSX if you are into that). As a consequence we have 0 transform function bugs, because we don't have a transform function.
- No magic: what you see is what you get, your code is not transformed to actually do something different than what you write, there are no surprises.
- No server support: for the time being this framework is focused on local-first rich applications, ~no server-related features are implemented: no hydration, no server components, no SSR, no streaming etc.
- Observable-based: observables are at the core of our reactivity system. The way it works is very different from a React-like system, it may be more challenging to learn, but it's well worth the effort.
- Work in progress: this is probably beta software, I'm working on it because I need something with great performance for Notable, I'm allergic to third-party dependencies, I'd like something with an API that resonates with me, and I wanted to deeply understand how the more solid Solid, which you should also check out, works.
Demos
You can find some demos and benchmarks below, more demos are contained inside the repository.
- Playground: https://codesandbox.io/s/woby-playground-7w2pxg
- Benchmark: https://krausest.github.io/js-framework-benchmark/current.html
- Counter: https://codesandbox.io/s/woby-demo-counter-23fv5
- Clock: https://codesandbox.io/s/woby-demo-clock-w1e7yb
- Emoji Counter: https://codesandbox.io/s/woby-demo-emoji-counter-j91iz2
- HyperScript: https://codesandbox.io/s/woby-demo-hyperscript-h4rf38
- HTML Template Literal: https://codesandbox.io/s/woby-demo-html-lvfeyo
- Single-file HTML: https://codesandbox.io/s/woby-demo-html-dueygt?file=/public/index.html
- Spiral: https://codesandbox.io/s/woby-demo-spiral-ux33p6
- Store Counter: https://codesandbox.io/s/woby-demo-store-counter-kvoqrw
- Triangle: https://codesandbox.io/s/woby-demo-triangle-l837v0
- Boxes: https://codesandbox.io/s/woby-demo-boxes-wx6rqb
APIs
| Methods | Components | Hooks | Types | Extras |
| ------------------------------------- | --------------------------------- | ------------------------------------------- | ------------------------------------------- | ------------------------------- |
| $
| Dynamic
| useAbortController
| Context
| Contributing
|
| $$
| ErrorBoundary
| useAbortSignal
| Directive
| Globals
|
| batch
| For
| useAnimationFrame
| DirectiveOptions
| JSX
|
| createContext
| ForIndex
| useAnimationLoop
| FunctionMaybe
| Tree Shaking
|
| createDirective
| ForValue
| useBoolean
| Observable
| TypeScript
|
| createElement
| Fragment
| useCleanup
| ObservableReadonly
| |
| h
| If
| useContext
| ObservableMaybe
| |
| html
| Portal
| useDisposed
| ObservableOptions
| |
| isBatching
| Suspense
| useEffect
| Resource
| |
| isObservable
| Switch
| useError
| StoreOptions
| |
| isServer
| Ternary
| useEventListener
| | |
| isStore
| | useFetch
| | |
| lazy
| | useIdleCallback
| | |
| render
| | useIdleLoop
| | |
| renderToString
| | useInterval
| | |
| resolve
| | useMemo
| | |
| store
| | useMicrotask
| | |
| template
| | usePromise
| | |
| untrack
| | useReaction
| | |
| | | useReadonly
| | |
| | | useResolved
| | |
| | | useResource
| | |
| | | useRoot
| | |
| | | useSelector
| | |
| | | useTimeout
| | |
Usage
This framework is simply a view layer built on top of the Observable library oby
, knowing how that works is necessary to understand how this works.
This framework basically re-exports everything that oby
exports, sometimes with a slightly different interface, adjusted for usage as components or hooks, plus some additional functions.
The following is going to be a very shallow documentation of the API. As I mentioned this probably isn't production-grade software, it may become that in the future though, are you interested?
Methods
The following top-level functions are provided.
$
This function is just the default export of oby
, it can be used to wrap a value in an observable.
No additional methods are attached to this function. Everything that oby
attaches to it is instead exported as components and hooks.
Interface:
function $ <T> (): Observable<T | undefined>;
function $ <T> ( value: undefined, options?: ObservableOptions<T | undefined> ): Observable<T | undefined>;
function $ <T> ( value: T, options?: ObservableOptions<T> ): Observable<T>;
Usage:
import {$} from 'woby';
// Create an observable without an initial value
$<number> ();
// Create an observable with an initial value
$(1);
// Create an observable with an initial value and a custom equality function
const equals = ( value, valuePrev ) => Object.is ( value, valuePrev );
const o = $( 1, { equals } );
// Create an observable with an initial value and a special "false" equality function, which is a shorthand for `() => false`, which causes the observable to always emit when its setter is called
const oFalse = $( 1, { equals: false } );
// Getter
o (); // => 1
// Setter
o ( 2 ); // => 2
// Setter via a function, which gets called with the current value
o ( value => value + 1 ); // => 3
// Setter that sets a function, it has to be wrapped in another function because the above form exists
const noop = () => {};
o ( () => noop );
$$
This function unwraps a potentially observable value.
Interface:
function $$ <T> ( value: T ): (T extends ObservableReadonly<infer U> ? U : T);
Usage:
import {$$} from 'woby';
// Getting the value out of an observable
const o = $(123);
$$ ( o ); // => 123
// Getting the value out of a function
$$ ( () => 123 ); // => 123
// Getting the value out of an observable but not out of a function
$$ ( o, false ); // => 123
$$ ( () => 123, false ); // => () => 123
// Getting the value out of a non-observable and non-function
$$ ( 123 ); // => 123
batch
This function holds onto updates within its scope and flushes them out once it exits.
Interface:
function batch <T> ( fn: () => T ): T;
function batch <T> ( value: T ): T;
Usage:
import {batch} from 'woby';
batch // => Same as require ( 'oby' ).batch
createContext
This function creates a context object, optionally with a default value, which can later be used to provide a new value for the context or to read the current value.
A context's Provider
will register the context with its children, which is always what you want, but it can lead to messy code due to nesting.
A context's register
function will register the context with the current parent observer, which is usually only safe to do at the root level, but it will lead to very readable code.
Interface:
type ContextProvider<T> = ( props: { value: T, children: JSX.Element } ) => JSX.Element;
type ContextRegister<T> = ( value: T ) => void;
type Context<T> = { Provider: ContextProvider<T>, register: ContextRegister<T> };
function createContext <T> ( defaultValue?: T ): Context<T>;
Usage:
import {createContext, useContext} from 'woby';
const App = () => {
const Context = createContext ( 123 );
return (
<>
{() => {
const value = useContext ( Context );
return <p>{value}</p>;
}}
<Context.Provider value={312}>
{() => {
const value = useContext ( Context );
return <p>{value}</p>;
}}
</Context.Provider>
</>
);
};
createDirective
This function creates a directive provider, which can be used to register a directive with its children.
A directive is a function that always receives an Element
as its first argument, which is basically a ref to the target element, and arbitrary user-provided arguments after that.
Each directive has a unique name and it can be called by simply writing use:directivename={[arg1, arg2, ...argN]]}
in the JSX.
Directives internally are registered using context providers, so you can also override directives for a particular scope just by registering another directive with the same name closer to where you are reading it.
A directive's Provider
will register the directive with its children, which is always what you want, but it can lead to messy code due to nesting.
A directive's register
function will register the directive with the current parent observer, which is usually only safe to do at the root level, but it will lead to very readable code.
Interface:
type DirectiveFunction = <T extends unknown[]> ( ref: Element, ...args: T ) => void;
type DirectiveProvider = ( props: { children: JSX.Element } ) => JSX.Element;
type DirectiveRef<T extends unknown[]> = ( ...args: T ) => (( ref: Element ) => void);
type DirectiveRegister = () => void;
type Directive = { Provider: DirectiveProvider, ref: DirectiveRef, register: DirectiveRegister };
function createDirective <T extends unknown[] = []> ( name: string, fn: DirectiveFunction<T>, options?: DirectiveOptions ): Directive;
Usage:
import {createDirective, useEffect} from 'woby';
// First of all if you are using TypeScript you should extend the "JSX.Directives" interface, so that TypeScript will know about your new directive
namespace JSX {
interface Directives {
tooltip: [title: string] // Mapping the name of the directive to the array of arguments it accepts
}
}
// Then you should create a directive provider
const TooltipDirective = createDirective ( 'tooltip', ( ref, title: string ) => {
useEffect ( () => {
if ( !ref () ) return; // The element may not be available yet, or it might have been unmounted
// Code that implements a tooltip for the given element here...
});
});
// Then you can use the new "tooltip" directive anywhere inside the "TooltipDirective.Provider"
const App = () => {
return (
<TooltipDirective.Provider>
<input value="Placeholder..." use:tooltip={['This is a tooltip!']} />
</TooltipDirective.Provider>
);
};
// You can also use directives directly by padding them along as refs
const App = () => {
return <input ref={TooltipDirective.ref ( 'This is a tooltip!' )} value="Placeholder..." />;
};
createElement
This is the internal function that will make DOM nodes and call/instantiate components, it will be called for you automatically via JSX.
Interface:
function createElement <P = {}> ( component: JSX.Component<P>, props: P | null, ...children: JSX.Element[] ): () => JSX.Element);
Usage:
import {createElement} from 'woby';
const element = createElement ( 'div', { class: 'foo' }, 'child' ); // => () => HTMLDivElement
h
This function is just an alias for the createElement
function, it's more convenient to use if you want to use Voby in hyperscript mode just because it has a much shorter name.
Interface:
function h <P = {}> ( component: JSX.Component<P>, props: P | null, ...children: JSX.Element[] ): () => JSX.Element);
Usage:
import {h} from 'woby';
const element = h ( 'div', { class: 'foo' }, 'child' ); // => () => HTMLDivElement
html
This function provides an alternative way to use the framework, without writing JSX or using the h
function manually, it instead allows you to write your markup as tagged template literals.
htm
is used under the hood, read its documentation.
Interface:
function html ( strings: TemplateStringsArray, ...values: any[] ): JSX.Element;
Usage:
import {html, If} from 'woby';
const Counter = (): JSX.Element => {
const value = $(0);
const increment = () => value ( prev => prev + 1 );
const decrement = () => value ( prev => prev - 1 );
return html`
<h1>Counter</h1>
<p>${value}</p>
<button onClick=${increment}>+</button>
<button onClick=${decrement}>-</button>
`;
};
// Using a custom component without registering it
const NoRegistration = (): JSX.Element => {
return html`
<${If} when=${true}>
<p>content</p>
</${If}>
`;
};
// Using a custom component after registering it, so you won't need to interpolate it anymore
html.register ({ If });
const NoRegistration = (): JSX.Element => {
return html`
<If when=${true}>
<p>content</p>
</If>
`;
};
isBatching
This function tells you if batching is currently active or not.
Interface:
function isBatching (): boolean;
Usage:
import {batch, isBatching} from 'woby';
// Checking if currently batching
isBatching (); // => false
batch ( () => {
isBatching (); // => true
});
isBatching (); // => false
isObservable
This function tells you if a variable is an observable or not.
Interface:
function isObservable <T = unknown> ( value: unknown ): value is Observable<T> | ObservableReadonly<T>;
Usage:
import {$, isObservable} from 'woby';
isObservable ( 123 ); // => false
isObservable ( $(123) ); // => true
isServer
This function tells you if your code is executing in a browser environment or not.
Interface:
function isServer (): boolean;
Usage:
import {isServer} from 'woby';
isServer (); // => true or false
isStore
This function tells you if a variable is a store or not.
Interface:
function isStore ( value: unknown ): boolean;
Usage:
import {store, isStore} from 'woby';
isStore ( {} ); // => false
isStore ( store ( {} ) ); // => true
lazy
This function creates a lazy component, which is loaded via the provided function only when/if needed.
This function uses useResource
internally, so it's significant for Suspense
too.
Interface:
type LazyComponent<P = {}> = ( props: P ) => ObservableReadonly<Child>;
type LazyFetcher<P = {}> = () => Promise<{ default: JSX.Component<P> } | JSX.Component<P>>;
type LazyResult<P = {}> = LazyComponent<P> & ({ preload: () => Promise<void> });
function lazy <P = {}> ( fetcher: LazyFetcher<P> ): LazyResult<P>;
Usage:
import {lazy} from 'woby';
const LazyComponent = lazy ( () => import ( './component' ) );
render
This function mounts a component inside a provided DOM element and returns a disposer function for unmounting it and stopping all reactivity inside it.
Interface:
function render ( child: JSX.Element, parent?: HTMLElement | null ): Disposer;
Usage:
import {render} from 'woby';
const App = () => <p>Hello, World!</p>;
const dispose = render ( <App />, document.body );
dispose (); // Unmounted and all reactivity inside it stopped
renderToString
This works just like render
, but it returns a Promise to the HTML representation of the rendered component.
This is currently implemented in a way that works only inside a browser-like environement, so you'll need to use JSDOM or similar for this to work server-side, but it can work server-side too potentially.
This function automatically waits for all Suspense
boundaries to resolve before returning.
Interface:
function renderToString ( child: JSX.Element ): Promise<string>;
Usage:
import {renderToString} from 'woby';
const App = () => <p>Hello, World!</p>;
const html = await renderToString ( <App /> );
resolve
This function basically resolves any reactivity inside the passed argument, basically replacing every function it finds with a memo to the value of that function.
You may never need to use this function yourself, but it's necessary internally at times to make sure that a child value is properly tracked by its parent computation.
Interface:
type ResolvablePrimitive = null | undefined | boolean | number | bigint | string | symbol;
type ResolvableArray = Resolvable[];
type ResolvableObject = { [Key in string | number | symbol]?: Resolvable };
type ResolvableFunction = () => Resolvable;
type Resolvable = ResolvablePrimitive | ResolvableObject | ResolvableArray | ResolvableFunction;
function resolve <T> ( value: T ): T extends Resolvable ? T : never;
Usage:
import {resolve} from 'woby';
resolve // => Same as require ( 'oby' ).resolve
store
This function returns a deeply reactive version of the passed object, where property accesses and writes are automatically interpreted as Observables reads and writes for you.
Interface:
function store <T> ( value: T, options?: StoreOptions ): T;
Usage:
import {store} from 'woby';
store // => Same as require ( 'oby' ).store
template
This function enables constructing elements with Solid-level performance without using the Babel transform, but also without the convenience of that.
It basically works like sinuous's template function, but with a cleaner API, since you don't have to access your props any differently inside the template here.
Basically you can use this to wrap a component that doesn't directly create any observables or call any hooks to significanly improve performance when instantiating that component.
Interface:
function template <P = {}> ( fn: (( props: P ) => JSX.Element) ): (( props: P ) => () => Element);
Usage:
import {template} from 'woby';
const Row = template ( ({ id, cls, label, onSelect, onRemove }) => { // Now Row is super fast to instantiate
return (
<tr class={cls}>
<td class="col-md-1">{id}</td>
<td class="col-md-4">
<a onClick={onSelect}>{label}</a>
</td>
<td class="col-md-1">
<a onClick={onRemove}>
<span class="glyphicon glyphicon-remove" ariaHidden={true}></span>
</a>
</td>
<td class="col-md-6"></td>
</tr>
);
});
const Table = () => {
const rows = [ /* props for all your rows here */ ];
return rows.map ( row => <Row {...row}> );
};
untrack
This function executes the provided function without creating dependencies on observables retrieved inside it.
Interface:
function untrack <T> ( fn: () => T ): T;
function untrack <T> ( value: T ): T;
Usage:
import {untrack} from 'woby';
untrack // => Same as require ( 'oby' ).untrack
Components
The following components are provided.
Crucially some components are provided for control flow, since regular JavaScript control flow primitives are not reactive, and we need to have reactive alternatives to them to have great performance.
Dynamic
This component is just an alternative to createElement
that can be used in JSX, it's useful to create a new element dynamically.
Interface:
function Dynamic <P = {}> ( props: { component: ObservableMaybe<JSX.Component<P>, props?: FunctionMaybe<P | null>, children?: JSX.Element }): JSX. Element;
Usage:
import {Dynamic} from 'woby';
const App = () => {
const heading = 'h2';
return (
<Dynamic component={heading}>
Some content
</Dynamic>
);
};
ErrorBoundary
The error boundary catches errors thrown inside it, and renders a fallback component when that happens.
Interface:
function ErrorBoundary ( props: { fallback: JSX.Element | (( props: { error: Error, reset: Callback } ) => JSX.Element), children: JSX.Element }): ObservableReadonly<JSX.Element>;
Usage:
import {ErrorBoundary} from 'woby';
const Fallback = ({ reset, error }: { reset: () => void, error: Error }) => {
return (
<>
<p>Error: {error.message}</p>
<button onClick={error}>Recover</button>
</>
);
};
const SomeComponentThatThrows = () => {
throw 'whatever';
};
const App = () => {
return (
<ErrorBoundary fallback={Fallback}>
<SomeComponentThatThrows />
</ErrorBoundary>
);
};
For
This component is the reactive alternative to natively mapping over an array.
It must be called with an array, or a function that returns an array, of unique values, and each of them are passed to the child function to render something.
Interface:
function For <T> ( props: { values: FunctionMaybe<readonly T[]>, fallback?: JSX.Element, children: (( value: T, index: FunctionMaybe<number> ) => JSX.Element) }): ObservableReadonly<JSX.Element>;
Usage:
import {For} from 'woby';
const App = () => {
const numbers = [1, 2, 3, 4, 5];
return (
<For values={numbers}>
{( value ) => {
return <p>Value: {value}</p>
}}
</For>
);
};
ForIndex
This component is a reactive alternative to natively mapping over an array, but it takes the index as the unique key instead of the value.
This is an alternative to For
that uses the index of the value in the array for caching, rather than the value itself.
It's recommended to use ForIndex
for arrays containing duplicate values and/or arrays containing primitive values, and For
for everything else.
The passed function will always be called with a read-only observable containing the current value at the index being mapped.
Interface:
type Value<T = unknown> = T extends ObservableReadonly<infer U> ? ObservableReadonly<U> : ObservableReadonly<T>;
function ForIndex <T> ( props: { values: FunctionMaybe<readonly T[]>, fallback?: JSX.Element, children: (( value: Value<T>, index: number ) => JSX.Element) }): ObservableReadonly<JSX.Element>;
Usage:
import {ForIndex} from 'woby';
const App = () => {
const numbers = [1, 2, 3, 4, 5];
return (
<ForIndex values={numbers}>
{( value ) => {
return <p>Double value: {() => value () ** 2}</p>
}}
</ForIndex>
);
};
ForValue
This component is a reactive alternative to natively mapping over an array, but it caches results for values that didn't change, and repurposes results for items that got discarded for new items that need to be rendered.
This is an alternative to For
and ForIndex
that enables reusing the same result for different items, when possible. Reusing the same result means also reusing everything in it, including DOM nodes.
Basically Array.prototype.map
doesn't wrap the value nor the index in an observable, For
wraps the index only in an observable, ForIndex
wraps the value only in an observable, and ForValue
wraps both the value and the index in observables.
This is useful for use cases like virtualized rendering, where For
would cause some nodes to be discarded and others to be created, ForIndex
would cause all nodes to be repurposed, but ForValue
allows you to only repurpose the nodes that would have been discareded by For
, not all of them.
This is a more advanced component, it's recommended to simply use For
or ForIndex
, until you really understand how to squeeze extra performance with this, and you actually need that performance.
Interface:
type Value<T = unknown> = T extends ObservableReadonly<infer U> ? ObservableReadonly<U> : ObservableReadonly<T>;
function ForValue <T> ( props: { values: FunctionMaybe<readonly T[]>, fallback?: JSX.Element, children: (( value: Value<T>, index: ObservableReadonly<number> ) => JSX.Element) }): ObservableReadonly<JSX.Element>;
Usage:
import {ForValue} from 'woby';
const App = () => {
const numbers = [1, 2, 3, 4, 5];
return (
<ForValue values={numbers}>
{( value ) => {
return <p>Double value: {() => value () ** 2}</p>
}}
</ForValue>
);
};
Fragment
This is just the internal component used for rendering fragments: <></>
, you probably would never use this directly even if you are not using JSX, since you can return plain arrays from your components anyway.
Interface:
function Fragment ( props: { children: JSX.Element }): JSX.Element;
Usage:
import {Fragment} from 'woby';
const App = () => {
return (
<Fragment>
<p>child 1</p>
<p>child 2</p>
</Fragment>
);
};
If
This component is the reactive alternative to the native if
.
If a function is passed as the children then it will be called with a read-only observable that contains the current, always truthy, value of the "when" condition.
Interface:
type Truthy<T = unknown> = Extract<T, number | bigint | string | true | object | symbol | Function>;
function If <T> ( props: { when: FunctionMaybe<T>, fallback?: JSX.Element, children: JSX.Element | (( value: (() => Truthy<T>) ) => JSX.Element) }): ObservableReadonly<JSX.Element>;
Usage:
import {If} from 'woby';
const App = () => {
const visible = $(false);
const toggle = () => visible ( !visible () );
return (
<>
<button onClick={toggle}>Toggle</button>
<If when={visible}>
<p>Hello!</p>
</If>
</>
);
};
Portal
This component mounts its children inside a provided DOM element, or inside document.body
otherwise.
The mount
prop can also be an observable, if its value changes the portal is reparented.
The when
prop can be used to apply the portal conditionally, if it explicitly resolves to false then children are mounted normally, as if they weren't wrapped in a portal.
Events will propagate natively, according to the resulting DOM hierarchy, not the components hierarchy.
Interface:
function Portal ( props: { when: boolean, mount?: JSX.Element, wrapper?: JSX.Element, children: JSX.Element }): (() => JSX.Element | null) & ({ metadata: { portal: HTMLDivElement } });
Usage:
import Portal from 'woby';
const Modal = () => {
// Some modal component maybe...
};
const App = () => {
return (
<Portal mount={document.body}>
<Modal />
</Portal>
);
};
Suspense
This component is like If
, the reactive alternative to the native if
, but the fallback branch is shown automatically while there are some resources loading in the main branch, and the main branch is kept alive under the hood.
So this can be used to show some fallback content while the actual content is loading in the background.
This component relies on useResource
to understand if there's a resource loading or not.
This component also supports a manual "when" prop for manually deciding whether the fallback branch should be rendered or not.
Interface:
function Suspense ( props: { when?: FunctionMaybe<unknown>, fallback?: JSX.Element, children: JSX.Element }): ObservableReadonly<JSX.Element>;
Usage:
import {Suspense} from 'woby';
const App = () => {
const Content = () => {
const resource = useResource ( () => makeSomePromise () );
return (
<If when={() => !resource ().pending && !resource ().error}>
{resource ().value}
</If>
);
};
const Spinner = () => {
return <p>Loading...</p>;
};
return (
<Suspense fallback={<Spinner />}>
<Content />
</Suspense>
);
};
Switch
This component is the reactive alternative to the native switch
.
Interface:
function Switch <T> ( props: { when: FunctionMaybe<T>, fallback?: JSX.Element, children: JSX.Element }): ObservableReadonly<JSX.Element>;
Switch.Case = function <T> ( props: { when: T, children: JSX.Element } ): (() => JSX.Element) & ({ metadata: [T, JSX.Element] });
Switch.Default = function ( props: { children: JSX.Element } ): (() => JSX.Element) & ({ metadata: [JSX.Element] });
Usage:
import {Switch} from 'woby';
const App = () => {
const value = $(0);
const increment = () => value ( value () + 1 );
const decrement = () => value ( value () - 1 );
return (
<>
<Switch when={value}>
<Switch.Case when={0}>
<p>0, the boundary between positives and negatives! (?)</p>
</Switch.Case>
<Switch.Case when={1}>
<p>1, the multiplicative identity!</p>
</Switch.Case>
<Switch.Default>
<p>{value}, I don't have anything interesting to say about that :(</p>
</Switch.Default>
</Switch>
<button onClick={increment}>+</button>
<button onClick={decrement}>-</button>
</>
);
};
Ternary
This component is the reactive alternative to the native ternary operator.
The first child will be rendered when the condition is truthy, otherwise the second child will be rendered.
Interface:
function Ternary ( props: { when: FunctionMaybe<unknown>, children: [JSX.Element, JSX.Element] } ): ObservableReadonly<JSX.Element>;
Usage:
import {Ternary} from 'woby';
const App = () => {
const visible = $(false);
const toggle = () => visible ( !visible () );
return (
<>
<button onClick={toggle}>Toggle</button>
<Ternary when={visible}>
<p>Visible :)</p>
<p>Invisible :(</p>
</Ternary>
</>
);
};
Hooks
The following hooks are provided.
Many of these are just functions that oby
provides, re-exported as use*
functions, the rest are largely just alternatives to web built-ins that can also accept observables as arguments and can dispose of themselves automatically when the parent computation is disposed.
Hooks are just regular functions, if their name starts with use
then we call them hooks just because.
useAbortController
This hook is just an alternative to new AbortController ()
that automatically aborts itself when the parent computation is disposed.
Interface:
function useAbortController ( signals?: ArrayMaybe<AbortSignal> ): AbortController;
Usage:
import {useAbortController} from 'woby';
const controller = useAbortController ();
useAbortSignal
This hook is just a convenient alternative to useAbortController
, if you are only interested in its signal, which is automatically aborted when the parent computation is disposed.
Interface:
function useAbortSignal ( signals?: ArrayMaybe<AbortSignal> ): AbortSignal;
Usage:
import {useAbortSignal} from 'woby';
const signal = useAbortSignal ();
useAnimationFrame
This hook is just an alternative to requestAnimationFrame
that automatically clears itself when the parent computation is disposed.
Interface:
function useAnimationFrame ( callback: ObservableMaybe<FrameRequestCallback> ): Disposer;
Usage:
import {useAnimationFrame} from 'woby';
useAnimationFrame ( () => console.log ( 'called' ) );
useAnimationLoop
This hook is just a version of useAnimationFrame
that loops until the parent computation is disposed.
Interface:
function useAnimationLoop ( callback: ObservableMaybe<FrameRequestCallback> ): Disposer;
Usage:
import {useAnimationLoop} from 'woby';
useAnimationLoop ( () => console.log ( 'called' ) );
useBoolean
This hook is like the reactive equivalent of the !!
operator, it returns you a boolean, or a function to a boolean, depending on the input that you give it.
Interface:
function useBoolean ( value: FunctionMaybe<unknown> ): FunctionMaybe<boolean>;
Usage:
import {useBoolean} from 'woby';
useBoolean // => Same as require ( 'oby' ).boolean
useCleanup
This hook registers a function to be called when the parent computation is disposed.
Interface:
function useCleanup ( fn: () => void ): void;
Usage:
import {useCleanup} from 'woby';
useCleanup // => Same as require ( 'oby' ).cleanup
useContext
This hook retrieves the value out of a context object.
Interface:
function useContext <T> ( context: Context<T> ): T | undefined;
Usage:
import {createContext, useContext} from 'woby';
const App = () => {
const ctx = createContext ( 123 );
const value = useContext ( ctx );
return <p>{value}</p>;
};
useDisposed
This hook returns a boolean read-only observable that is set to true
when the parent computation gets disposed of.
Interface:
function useDisposed (): ObservableReadonly<boolean>;
Usage:
import {useDisposed} from 'woby';
useDisposed // => Same as require ( 'oby' ).disposed
useEffect
This hook registers a function to be called when any of its dependencies change. If a function is returned it's automatically registered as a cleanup function.
Interface:
function useEffect ( fn: () => (() => void) | void ): (() => void);
Usage:
import {useEffect} from 'woby';
useEffect // => Same as require ( 'oby' ).effect
useError
This hook registers a function to be called when the parent computation throws.
Interface:
function useError ( fn: ( error: Error ) => void ): void;
Usage:
import {useError} from 'woby';
useError // => Same as require ( 'oby' ).error
useEventListener
This hook is just an alternative to addEventListener
that automatically clears itself when the parent computation is disposed.
Interface:
function useEventListener ( target: FunctionMaybe<EventTarget>, event: FunctionMaybe<string>, handler: ObservableMaybe<( event: Event ) => void>, options?: FunctionMaybe<true | AddEventListenerOptions> ): Disposer;
Usage:
import {useEventListener} from 'woby';
useEventListener ( document, 'click', console.log );
useFetch
This hook wraps the output of a fetch request in an observable, so that you can be notified when it resolves or rejects. The request is also aborted automatically when the parent computation gets disposed of.
This hook uses useResource
internally, so it's significant for Suspense
too.
Interface:
function useFetch ( request: FunctionMaybe<RequestInfo>, init?: FunctionMaybe<RequestInit> ): ObservableReadonly<Resource<Response>>;
Usage:
import {useFetch} from 'woby';
const App = () => {
const state = useFetch ( 'https://my.api' );
return state.on ( state => {
if ( state.pending ) return <p>pending...</p>;
if ( state.error ) return <p>{state.error.message}</p>;
return <p>Status: {state.value.status}</p>
});
};
useIdleCallback
This hook is just an alternative to requestIdleCallback
that automatically clears itself when the parent computation is disposed.
Interface:
function useIdleCallback ( callback: ObservableMaybe<IdleRequestCallback>, options?: FunctionMaybe<IdleRequestOptions> ): Disposer;
Usage:
import {useIdleCallback} from 'woby';
useIdleCallback ( () => console.log ( 'called' ) );
useIdleLoop
This hook is just a version of useIdleCallback
that loops until the parent computation is disposed.
Interface:
function useIdleLoop ( callback: ObservableMaybe<IdleRequestCallback>, options?: FunctionMaybe<IdleRequestOptions> ): Disposer;
Usage:
import {useIdleLoop} from 'woby';
useIdleLoop ( () => console.log ( 'called' ) );
useInterval
This hook is just an alternative to setInterval
that automatically clears itself when the parent computation is disposed.
Interface:
function useInterval ( callback: ObservableMaybe<Callback>, ms?: FunctionMaybe<number> ): Disposer;
Usage:
import {useInterval} from 'woby';
useInterval ( () => console.log ( 'called' ), 1000 );
useMemo
This hook is the crucial other ingredient that we need, other than observables themselves, to have a powerful reactive system that can track dependencies and re-execute computations when needed.
This hook registers a function to be called when any of its dependencies change, and the return of that function is wrapped in a read-only observable and returned.
Interface:
function useMemo <T> ( fn: () => T, options?: ObservableOptions<T | undefined> ): ObservableReadonly<T>;
Usage:
import {useMemo} from 'woby';
useMemo // => Same as require ( 'oby' ).memo
useMicrotask
This hook is just an alternative to queueMicrotask
that automatically clears itself when the parent computation is disposed, and that ensures things like contexts, error boundaries etc. keep working inside the microtask.
Interface:
function useMicrotask ( fn: () => void ): void;
Usage:
import {useMicrotask} from 'woby';
useMicrotask ( () => console.log ( 'called' ) );
usePromise
This hook wraps a promise in an observable, so that you can be notified when it resolves or rejects.
This hook uses useResource
internally, so it's significant for Suspense
too.
Interface:
function usePromise <T> ( promise: FunctionMaybe<Promise<T>> ): ObservableReadonly<Resource<T>>;
Usage:
import {usePromise} from 'woby';
const App = () => {
const request = fetch ( 'https://my.api' ).then ( res => res.json ( 0 ) );
const promise = usePromise ( request );
return resolved.on ( state => {
if ( state.pending ) return <p>pending...</p>;
if ( state.error ) return <p>{state.error.message}</p>;
return <p>{JSON.stringify ( state.value )}</p>
});
};
useReaction
This hook works just like useEffect
, expect that it's not affected by Suspense
.
This is an advanced hook mostly useful internally, you may never need to use this, useEffect
and useMemo
should suffice.
Interface:
function useReaction ( fn: () => (() => void) | void ): (() => void);
Usage:
import {useReaction} from 'woby';
useReaction // => Same as require ( 'oby' ).reaction
useReadonly
This hook creates a read-only observable out of another observable.
Interface:
function useReadonly <T> ( observable: Observable<T> | ObservableReadonly<T> ): ObservableReadonly<T>;
Usage:
import {useReadonly} from 'woby';
useReadonly // => Same as require ( 'oby' ).readonly
useResolved
This hook receives a value, or an array of values, potentially wrapped in functions and/or observables, and unwraps it/them.
If no callback is used then it returns the unwrapped value, otherwise it returns whatever the callback returns.
This is useful for handling reactive and non reactive values the same way. Usually if the value is a function, or always for convenience, you'd want to wrap the useResolved
call in a useMemo
, to maintain reactivity.
This is potentially a more convenient version of $$
, made especially for handling nicely arguments passed that your hooks receive that may or may not be observables.
Interface:
The precise interface for this function is insane, you can find it here: https://github.com/fabiospampinato/woby/blob/master/src/hooks/use_resolved.ts
Usage:
import {$, useResolved} from 'woby';
useResolved ( 123 ); // => 123
useResolved ( $(123) ); // => 123
useResolved ( () => 123 ); // => 123
useResolved ( () => 123, false ); // => () => 123
useResolved ( $(123), value => 321 ); // => 321
useResolved ( [$(123), () => 123], ( a, b ) => 321 ); // => 321
useResource
This hook wraps the result of a function call with an observable, handling the cases where the function throws, the result is an observable, the result is a promise or an observale that resolves to a promise, and the promise rejects, so that you don't have to worry about these issues.
This basically provides a unified way to handle sync and async results, observable and non observable results, and functions that throw and don't throw.
This function is also the mechanism through which Suspense
understands if there are things loading under the hood or not.
When the value
property is read while fetching, or when the latest
property is read the first time, or after an error, while fetching, then Suspense
boundaries will be triggered.
When the value
property or the latest
property are read after the fetch errored they will throw, triggering ErrorBoundary
.
The passed function is tracked and it will be automatically re-executed whenever any of the observables it reads change.
Interface:
function useResource <T> ( fetcher: (() => ObservableMaybe<PromiseMaybe<T>>) ): Resource<T>;
Usage:
import {useResource} from 'woby';
const fetcher = () => fetch ( 'https://my.api' );
const resource = useResource ( fetcher );
useRoot
This hook creates a new computation root, detached from any parent computation.
Interface:
function useRoot <T> ( fn: ( dispose: () => void ) => T ): T;
Usage:
import {useRoot} from 'woby';
useRoot // => Same as require ( 'oby' ).root
useSelector
This hook massively optimizes isSelected
kind of workloads.
Interface:
type SelectorFunction<T> = ( value: T ) => ObservableReadonly<boolean>;
function useSelector <T> ( source: () => T | ObservableReadonly<T> ): SelectorFunction<T>;
Usage:
import {useSelector} from 'woby';
useSelector // => Same as require ( 'oby' ).selector
useTimeout
This hook is just an alternative to setTimeout
that automatically clears itself when the parent computation is disposed.
Interface:
function useTimeout ( callback: ObservableMaybe<Callback>, ms?: FunctionMaybe<number> ): Disposer;
Usage:
import {useTimeout} from 'woby';
useTimeout ( () => console.log ( 'called' ), 1000 );
Types
Context
This type describes the object that createContext
gives you.
Interface:
type Context<T = unknown> = {
Provider ( props: { value: T, children: JSX.Element } ): JSX.Element,
register ( value: T ): void
};
Usage:
import {useContext} from 'woby';
import type {Context} from 'woby';
// Create an alternative useContext that throws if the context is not available
const useNonNullableContext = <T> ( context: Context<T> ): NonNullable<T> => {
const value = useContext ( context );
if ( value === null || value === undefined ) throw new Error ( 'Missing context' );
return value;
};
Directive
This type describes the object that createDirective
gives you.
Interface:
type Directive<Arguments extends unknown[] = []> = {
Provider: ( props: { children: JSX.Element } ) => JSX.Element,
ref: ( ...args: Arguments ) => (( ref: Element ) => void),
register: () => void
};
Usage:
import {$$, useEffect} from 'woby';
import type {Directive, FunctionMaybe} from 'woby';
// Example hook for turning a directive into a hook
const useDirective = <T extends unknown[] = []> ( directive: Directive<T> ) => {
return ( ref: FunctionMaybe<Element | undefined>, ...args: T ): void => {
useEffect ( () => {
const target = $$(ref);
if ( !target ) return;
directive.ref ( ...args )( target );
});
};
};
DirectiveOptions
This type describes the options object that the createDirective
function accepts.
Interface:
type DirectiveOptions = {
immediate?: boolean // If `true` the directive is called as soon as the node is created, otherwise it also waits for that node to be attached to the DOM
};
Usage:
import {createDirective} from 'woby';
// Create an regular, non-immediate, directive
const TooltipDirective = createDirective ( 'tooltip', ( ref, title: string ) => {
// Implementation...
});
// Create an immediate directive
const TooltipDirectiveImmediate = createDirective ( 'tooltip', ( ref, title: string ) => {
// Implementation...
}, { immediate: true } );
FunctionMaybe
This type says that something can be the value itself or a function that returns that value.
It's useful at times since some components, like If
, accept when
conditions wrapped in FunctionMaybe
.
Interface:
type FunctionMaybe<T> = (() => T) | T;
Usage:
import type {FunctionMaybe} from 'woby';
const SomeConditionalComponent = ( when: FunctionMaybe<boolean>, value: string ): JSX.Element => {
return (
<If when={when}>
{value}
</If>
);
};
Observable
This type says that something is a regular observable, which can be updated via its setter.
Interface:
type Observable<T> = {
(): T,
( value: T ): T,
( fn: ( value: T ) => T ): T
};
Usage:
import type {Observable} from 'woby';
const fn = ( value: Observable<boolean> ): void => {
value (); // Getting
value ( true ); // Setting
};
ObservableReadonly
This type says that something is a read-only observable, which can only be read but not updated.
Interface:
type ObservableReadonly<T> = {
(): T
};
Usage:
import type {ObservableReadonly} from 'woby';
const fn = ( value: ObservableReadonly<boolean> ): void => {
value (); // Getting
value ( true ); // This will throw!
};
ObservableMaybe
This type says that something can be the value itself or an observable to that value.
This is super useful if you want to write components and hooks that can accept either plain values or observables to those values.
Interface:
type ObservableMaybe<T> = Observable<T> | ObservableReadonly<T> | T;
Usage:
import type {ObservableMaybe} from 'woby';
const Button = ({ label }: { label: ObservableMaybe<string> }): JSX.Element => {
return <button>{label}</button>;
};
ObservableOptions
This type describes the options object that various functions can accept to tweak how the underlying observable works.
Interface:
type ObservableOptions<T> = {
equals?: (( value: T, valuePrev: T ) => boolean) | false
};
Usage:
import type {Observable, ObservableOptions} from 'woby';
import {$} from 'woby';
const createTimestamp = ( options?: ObservableOptions ): Observable<number> => {
return $( Date.now (), options );
};
Resource
This is the type of object that useResource
, usePromise
and useFetch
will return you.
It's an object that tells if whether the resource is loading or not, whether an error happened or not, if what the eventual resulting value is.
It's a read-only observable that holds the resulting object, but it also comes with helper methods for retrieving specific keys out of the object, which can make some code much cleaner.
Helper methods are memoized automatically for you.
Interface:
type ResourceStaticPending<T> = { pending: true, error?: never, value?: never, latest?: T };
type ResourceStaticRejected = { pending: false, error: Error, value?: never, latest?: never };
type ResourceStaticResolved<T> = { pending: false, error?: never, value: T, latest: T };
type ResourceStatic<T> = ResourceStaticPending<T> | ResourceStaticRejected | ResourceStaticResolved<T>;
type ResourceFunction<T> = { pending (): boolean, error (): Error | undefined, value (): T | undefined, latest (): T | undefined };
type Resource<T> = ObservableReadonly<ResourceStatic<T>> & ResourceFunction<T>;
Usage:
import type {ObservableReadonly, Resource} from 'woby';
const resource: Resource<Response> = useResource ( () => fetch ( 'https://my.api' ) );
// Reading the static object
resource ().pending; // => true | false
resource ().error; // => Error | undefined
resource ().value; // => Whatever the resource will resolve to
resource ().latest; // => Whatever the resource will resolve to, or the previous known resolved value if the resource is pending
// Using helper methods
resource.pending (); // => true | false
resource.error (); // => Error | undefined
resource.value (); // => Whatever the resource will resolve to
resource.latest (); // => Whatever the resource will resolve to, or the previous known resolved value if the resource is pending
StoreOptions
This type describes the options object that the store
function accepts.
Interface:
type StoreOptions = {
unwrap?: boolean
};
Usage:
import type {StoreOptions} from 'woby';
import {store} from 'woby';
const createStore = <T> ( value: T, options?: StoreOptions ): T => {
return store ( value, options );
};
Extras
Extra features and details.
Contributing
If you'd like to contribute to this repo you should take the following steps to install Voby locally:
git clone https://github.com/vobyjs/woby.git
cd voby
npm install
npm run compile
Then you can run any of the demos locally like this:
# Playground
npm run dev
# Counter
npm run dev:counter
# Benchmark
npm run dev:benchmark
Globals
The following globals are supported, some of them can be used to tweak how the framework works internally.
VOBY
: iftrue
, then Voby is used in the current client page. This is also used internally to detect if Voby has been loaded multiple times within the same page, which is not supported.VOBY_HMR
: iftrue
, then Voby will catch errors that happen during diffing and log them to the console instead, keeping your page working after an HMR update event in some case. Fine-grainined support for HMR is not implemented (yet?).
JSX
JSX is supported out of the box, as a rule of thumb it's very similar to how React's JSX works, but with some differences.
- The value provided to an attribute can always be either just the plain value itself, an observable to that value, or a function to that value. If an observable or a function is provided then that attribute will update itself in a fine-grained manner.
- There's no "key" attribute because it's unnecessary.
- Only refs in the function form are supported, so you are incentivized to simply use observables for them too.
- The "ref" attribute can also accept an array of functions to call, for convenience.
- You can simply just use "class" instead of "className".
- The "class" attribute can also accept an object of classes or an array of classes, for convenience.
- SVGs are supported out of the box and will also be updated in a fine-grained manner.
- The "innerHTML", "outerHTML" and "textContent" attributes are forbidden, as they are largely just footguns or non-idiomatic.
- A React-like "dangerouslySetInnerHTML" attribute is supported for setting some raw HTML.
- Numbers set as values for style properties that require a unit to be provided will automatically be suffixed with "px".
- Using CSS variables in the "style" object is supported out of the box.
- The following events are delegated, automatically:
beforeinput
,click
,dblclick
,focusin
,focusout
,input
,keydown
,keyup
,mousedown
,mouseup
. - Events always bubble according to the natural DOM hierarchy, there's no special bubbling logic for
Portal
. - Class components, but with no lifecycle callbacks, are supported too. They got thrown away with the bath water by other frameworks, but organizing internal methods in a class and assigning that class to refs automatically is actually a really nice feature.
Tree Shaking
Voby is released as a tree-shakeable ESM module. The functions you don't use simply won't be included in the final bundle.
TypeScript
There are two main actions needed to make Voby work with TypeScript.
- Voby is an ESM-only framework, so you might need to mark your package as ESM too in order to use it, you can do that by putting the following in your
package.json
:"type": "module"
- You should instruct TypeScript to load the correct JSX types by putting the following in your
tsconfig.json
:{ "compilerOptions": { "jsx": "react-jsx", "jsxImportSource": "woby" } }
- Optionally, if you don't want to use a bundler or if you are using a bundler for which a plugin hasn't been written yet you can just define a "React" variable in scope and just use the JSX transform for React:
import * as React from 'woby';
Thanks
- S: for paving the way to this awesome reactive way of writing software.
- sinuous/observable: for making me fall in love with Observables and providing a good implementation that this library was originally based on.
- solid: for being a great sort of reference implementation, popularizing Signal-based reactivity, and having built a great community.
- trkl: for being so inspiringly small.
License
MIT © Fabio Spampinato