README.md

react-solid-flow

SolidJS-inspired basic control-flow components and everyday async state hook library for React

It fulfills everyday needs: iteration, conditional display, Portals, ErrorBoundaries, fetching and displaying async data, etc.

• Native Typescript support
• Lightweight: (5kb minified, 2.5kb gzip), tree-shakable,
• Zero third-party dependencies, except React and React-DOM
• Modern: React 16.8+ .. 18.x, no legacy APIs or weird hacks
• Fully tested
• Easy to use
• Hooks and components for performing async operations, handling cancellations, mutations, race conditions, and more
• Mostly SolidJS compatible interface (where it makes sense in the React context)
• Covers common pitfalls (missed keys in maps, primitives as children, etc.)
• Made to be effective in React 16 and 17 and compatible with older webpack setups
• ⚡⚡💩💩 bLaZinGly FaSt 💩💩⚡⚡

Installation

npm install react-solid-flow

Usage

Components

For

function For<T, U extends ReactNode>(props: {
  each: ReadonlyArray<T> | undefined | null;
  children: ReactNode | ((item: T, idx: number) => U);
  fallback?: ReactNode;
}): ReactElement | null;

import { For } from "react-solid-flow";

<For each={collection} fallback="list is empty!">
  {(i) => <li key={i.id}>{i.name}</li>}
</For>

Rendering a collection of items from the each prop.

The children prop can be either a render prop function (more useful) or a static element.

If each isn't an array or has zero length, display the optional fallback.

Any nullish child is omitted. If every child is omitted, the fallback prop is shown.

You can specify a key prop directly on the root element of a child, using item's data. If the key isn't specified or is falsy, then array index added as the key automatically to avoid non-keyed items in the collection.

Show

function Show<T>(props: {
  when: T | undefined | null | false;
  children: ReactNode | ((item: NonNullable<T>) => ReactNode);
  fallback?: ReactNode;
}): ReactElement | null;

import { Show } from "react-solid-flow";

<Show when={parentSeen === 'mom'} fallback={<h3>nevermind...</h3>}>
  <h2>Hi mom!</h2>
</Show>

Conditionally renders, depending on truthiness of the when prop, either the children prop or (optionally) the fallback prop.

Switch / Match

function Switch(props: {
  children: ReactNode;
  fallback?: ReactNode;
}): ReactElement | null;

function Match<T>(props: {
  when: T | undefined | null | false;
  children?: ReactNode | ((item: NonNullable<T>) => ReactNode);
}): ReactElement | null;

import { Switch, Match } from "react-solid-flow";

<Switch fallback={<h3>nevermind...</h3>}>
  <Match when={parentSeen === "mom"}>
    Hi Mom!
  </Match>
  <Match when={parentSeen === "dad"}>
    Hi Dad!
  </Match>
</Switch>

Akin to switch-case, it renders one of the mutually exclusive conditions (described in the when prop of the Match component) of a switch.

The Match component should be a direct descendant of the Switch component, and only the first Match with a truthy when prop will be rendered.

If no Match component has a truthy when prop, the optional fallback prop will be shown.

ErrorBoundary

class ErrorBoundary extends Component<{
  fallback?: ReactNode | ((err: unknown, reset: () => void) => ReactNode);
  children?: ReactNode;
  onCatch?: (error: unknown, errorInfo: unknown) => void;
}> {}

import { ErrorBoundary } from "react-solid-flow";

<ErrorBoundary fallback={(err, reset) => (
  <div className="panel-danger">
    I failed miserably: <code>{String(err)}</code>
    <button type="button" onClick={reset}>
      Try again!
    </button>
  </div>
)}>
  <SomePotentiallyFailingComponent />
</ErrorBoundary>

General error boundary that catches synchronous errors in renders and displays the fallback content.

The fallback prop can be a static element or a render prop function, which receives the occurred error and the reset callback as its arguments.

A call to the reset function clears the occurred error and performs a re-render of children after that.

Await

export interface ResourceLike<T> {
  loading?: boolean;
  data: Awaited<T> | undefined;
  error: unknown;
}

function Await<T>(props: {
  for: ResourceLike<T>;
  fallback?: (() => ReactNode) | ReactNode;
  catch?: ((err: unknown) => ReactNode) | ReactNode;
  children?: ((data: Awaited<T>) => ReactNode) | ReactNode;
}): ReactElement | null;

A component for displaying resource-like async data. It can be used with a resource returned by the useResource hook in this library, or any other object that conforms to the required interface (such as responses from the Apollo Client).

import { Await, useResource } from "react-solid-flow";
// See description of useResource hook bellow.
const [ resource ] = useResource(() => fetch(`/api/v1/employees`).then(r => sr.json()));

<Await
  for={resource}
  fallback="loading..."
  catch={(err) => <div>Error: {String(err)}</div>}
>
  {(data) => <div>Resolved data: {data}</div>}
</Await>

Dynamic

function Dynamic<T extends {}, TRef>(
  props: T & {
    ref?: Ref<TRef>;
    children?: any;
    component?: ComponentType<T> | string | keyof JSX.IntrinsicElements;
  }
): ReactElement | null;

import { Dynamic } from "react-solid-flow";

<Dynamic component={isLink ? "a" : "span"} title="Foo" {...someOtherProps}>
  Maybe click me
</Dynamic>

This component allows you to insert an arbitrary component or tag and pass props to it (excluding the component prop).

Props are controlled by Typescript for Components, but not JSX intrinsic elements (such as "span", "div", etc.).

You can pass a ref to the target component. It's type won't be inferred automatically. so you need to type it.

Portal

function Portal(props: {
  mount?: Element | DocumentFragment | string;
  children?: ReactNode;
}): ReactPortal | null;

import { Portal } from "react-solid-flow";

<Portal mount="#modal-container-id">
  <dialog>
    Hi Mom!
  </dialog>
</Portal>

This component renders children outside of the component hierarchy's root node. React events will still function as usual.

The mount prop can be either a native node or a query selector for such a node.

If no node is provided, the component will render nothing.

Plase notice, it requires react-dom as its depenndency.

Hooks

Helpers for async state.

useResource

The useResource hook creates a Resource object that reflects the result of an asynchronous request performed by the fetcher function.

import { useResource } from "react-solid-flow";

const [{ data, error, loading }] = useResouce(
  (id, { signal }) => fetch(`/api/v1/employee/${id}`, { signal }).json(r => {
    if (!response.ok) {
      throw new Error(`HTTP error! Status: ${response.status}`);
    }
    return r.json();
  },
  [id]
);

// or better use Await component from above
return (
  <div className="employee">
    { loading ? (
      <span>Loading...</span>
    ) : error ? (
      <span>Error happened</span>
    ) : (
      {data.name}
    )}
  </div>
);

API signature:

function useResource<T, TArgs extends readonly any[]>(
  fetcher:
    | ((...args: [ ...TArgs, FetcherOpts ]) => Promise<T> | T)
    | ((...args: [ ...TArgs ]) => Promise<T> | T),
  deps: [...TArgs] = [] as unknown as [...TArgs],
  opts?: ResourceOptions<T>
): ResourceReturn<T, TArgs>;

type ResourceReturn<T, TArgs extends readonly any[]> = [
  Resource<T>,
  {
    mutate: (v: Awaited<T>) => void;
    refetch: (...args: TArgs) => Promise<T> | T;
    abort: (reason?: any) => void;
  }
];

type ResourceOptions<T> = {
  initialValue?: Awaited<T> | (() => Awaited<T>);
  onCompleted?: (data: Awaited<T>) => void;
  onError?: (error: unknown) => void;
  skipFirstRun?: boolean;
  skipFnMemoization?: boolean;
};

interface FetcherOpts {
  refetching: boolean;
  signal: AbortSignal;
}

class Resource<T> implements ResourceLike<T> {
  loading: boolean;
  data: Awaited<T> | undefined;
  error: unknown;
  latest: Awaited<T> | undefined;
  state: ResourceState;

  constructor(init?: Partial<ResourceLike<T>>, previous?: { latest?: Awaited<T> });
  static from<T>(data: Promise<T> | Awaited<T> | undefined): Resource<T>;
  static getState(r: ResourceLike<unknown>): ResourceState;
}

type ResourceState = "unresolved" | "pending" | "ready" | "refreshing" | "errored";

The result of the fetcher call is stored in the data field of the resource. The loading field represents if there is a pending call to the fetcher, and if the fetcher call was rejected, then the rejection value is stored in the error field.

The latest field will return the last returned value. This can be useful if you want to show the out-of-date data while the new data is loading.

The fetcher function is called every time the dependencies array is changed.

The dependencies array is passed to the fetcher function as arguments and the FetcherOpts object containing AbortSignal and additional data is added as the last argument.

If the dependencies array is omitted, the fetcher is called only on mount.

The state field represents the current state of the resource:

state	data	loading	error
unresolved	No	No	No
pending	No	Yes	No
ready	Yes	No	No
refreshing	Yes	Yes	No
errored	No	No	Yes

The FetcherOpts's signal field should be directly passed to your fetch function (or any other async function that supports the AbortController signal) to abort it.

Every unsettled request will be aborted if the dependencies array has been changed or if the component that uses this hook unmounts.

The useResource hook performs checks for race conditions and avoids unmounted state updates, even if your fetcher function doesn't react to signal abortion.

The useResource hook is optimized to trigger only one re-render on each resource state change.

const Employee = ({ employeeId }) => {
  const [ { data, loading, error} ] = useResource(
    (id, { signal }) => fetch(`/api/v1/employee/${id}`, { signal }),
    [ employeeId ]
  );
};

The second value of the return tuple is the control object, which allows you to handle the resource imperatively.

• mutate: Allows you to directly change the resource value.
• refetch: Allows you to call the fetcher function manually with the required arguments. The FetcherOpts with an abort signal is added to the arguments automatically.
• abort: Allows you to abort the current fetcher call.

If the abort is performed with no reason or with an AbortError instance, the state is still considered pending/refreshing, the resource.error is not updated, and the onError callback is not called. Any other reason will result in an error state for the resource.

The resource will not be refetched until the dependencies change again.

useResourceOptions

The useResource hook accepts several options to customize its behavior:

• initial value: The value (or a sync function resolving to this value), to be used as the resource initial value. If an initial value is passed, it sets the initial state to either "ready" or "refreshing" (depending on whether skip or skipFirstRun opts are true or not.)
• onCompleted and onError: Callbacks that are called when the resource resolves or rejects respectively.
• skip: If set to true, it skips calls to the fetcher function, but it can still be called manually with the refresh function. This can be useful if you want to wait for certain dependencies to be in a certain state before calling the fetcher or if you want to trigger the fetcher only manually on some event.
• skipFirstRun: If set to true, it skips the first automatic trigger of the fetcher function. It will be triggered only after the dependencies change.
• skipFnMemoization: If set to true, the fetcher function will not be memoized, and its change will result in calls to it (the same way as if the dependencies array was changed).

To avoid flickering of content, the resource initial state depends on the skip and skipFirstRun options. If any of them is true, the resource state will be "unresolved" or "ready" depending on whether the initialValue is defined. If both of them are false, the resource state will be "pending" or "refreshing" correspondingly, so we can correctly show a preloader right away.

Currently, there are no plans to support Suspense. The possibility was investigated and abandoned until the React team at least formally approves the usage of Suspense for anything other than components lazy loading. Implementation of Suspense support will require some forms of global promise cache and cache busting, and most likely this implementation will come from React itself, so it feels like reinventing the wheel.

If you really want to use suspended data fetches, there are some 3d party libs for that, if you want a recomendation, there's suspend-react

Check out useResource examples to see different forms of it in action.

Contributing

If you have any ideas or suggestions or want to report a bug, feel free to write in the issues section or create a PR.

License

react-solid-flow is MIT licensed.