@solid-primitives/refs

@solid-primitives/refs

Collection of primitives, components and directives that help managing references to JSX elements, keeping track of mounted/unmounted elements.

Primitives:

• mergeRefs - Utility for using jsx refs both for local variables and providing it to the props.ref for component consumers.
• elements - Reactive signal that filters out non-element items from a signal array. (Can be used with children primitive)
• refs - Get signal references to Elements of the reactive input. Which were added, which were removed. (Can be used with children primitive)
• mapRemoved - Similar to Solid's mapArray, but you map the elements that were removed from source array. Leting you keep them for longer.
• resolveElements — Will resolve value to a flat list of HTML elements or a single element or null.

Directive:

• unmount - A directive that calls handler when the element get's unmounted from DOM.

Components:

• <Children> - Solid's children helper in component form. Access it's children elements by get property.
• <Refs> - Get up-to-date references of the multiple children elements.
• <Ref> - Get up-to-date reference to a single child element.

Types:

• RefProps - Component properties with types for ref
• ResolvedChildren - Type of resolved JSX elements provided by Solid's children helper.

Vanilla helpers:

• getChangedItems - Tells you which elements got added to the array, and which got removed
• getAddedItems - Tells you elements got added to the array
• getRemovedItems - Tells you which elements got removed from the array

Installation

npm install @solid-primitives/refs
# or
yarn add @solid-primitives/refs

Primitives

---

mergeRefs

Utility for using jsx refs both for local variables and providing it to the props.ref for component consumers.

How to use it

import { mergeRefs } from "@solid-primitives/refs";

interface ButtonProps {
  ref?: HTMLButtonElement | ((el: HTMLButtonElement) => void);
}

const Button = (props: ButtonProps) => {
  let ref!: HTMLButtonElement;
  onMount(() => {
    // use the local ref
  });
  return <button ref={mergeRefs(el => (ref = el), props.ref)} />;
};

// in consumer's component:
let ref!: HTMLButtonElement;
<Button ref={ref} />;

elements

Reactive signal that filters out non-element items from a signal array. (Can be used with children primitive)

How to use it

import { elements } from "@solid-primitives/refs";

const resolved = children(() => props.children);
const els = elements(resolved);
els(); // T: Element[]

// or narrow down the element type
const divs = elements(resolved, HTMLDivElement);
divs(); // T: HTMLDivElement[]

refs

Get signal references to Elements of the reactive input. Which were added, which were removed. (Can be used with children primitive)

Used internally by <Refs> component.

How to use it

import { refs } from "@solid-primitives/refs";

const resolved = children(() => props.children);
const [els, added, removed] = refs(resolved);
els(); // T: Element[]
added(); // T: Element[]
removed(); // T: Element[]

// or narrow down the element type
const [els, added, removed] = refs(resolved, HTMLDivElement);
els(); // T: HTMLDivElement[]
added(); // T: HTMLDivElement[]
removed(); // T: HTMLDivElement[]

mapRemoved

Reactively map removed items from a reactive signal array. If the mapping function return an element signal, this element will be placed in the array returned from primitive.

How to use it

import { mapRemoved } from "@solid-primitives/refs";

const MyComp = props => {
  const resolved = children(() => props.children);

  const combined = mapRemoved(resolved, (ref, index) => {
    const [el, setEl] = createSignal(ref);

    // apply styles/animations to removed element
    ref.style.filter = "grayscale(100%)";

    // computations can be created inside the mapping fn
    createEffect(() => {
      // index is a signal
      index();
    });

    const remove = () => {
      // ...later
      // by setting returned signal to undefined
      // element get's removed from combined array permanently
      setEl(undefined);
    };

    // you can return a signal with element to keep it in the combined array
    return el;
  });

  return combined;
};

resolveElements

Similarly to children() helper from solid-js will resolve provided value to a flat list of HTML elements or a single element or null. But doesn't create a computation.

import { resolveElements } from "@solid-primitives/refs";

const MyComponent: ParentComponent = props => {
  createEffect(() => {
    const resolved = resolveElements(props.children);
    resolved; // T: HTMLElement | HTMLElement[] | null
  });
  return "Don't access props.children here again — it'll create new dom nodes";
};

Directive

---

unmount

A directive that calls handler when the element get's unmounted from DOM.

Import

import { unmount } from "@solid-primitives/refs";
// place it somewhere in the code to prevent it from being tree-shaken
unmount;

How to use it

const [ref, setRef] = createSignal<Element | undefined>();

<div ref={el => setRef(el)} use:unmount={() => setRef(undefined)}>
  Hello
</div>;

Components

---

<Children>

Solid's children helper in component form. Access it's children elements by get property.

How to use it

import {Children, ResolvedJSXElement} from "@solid-primitives/refs"

// typing as JSX.Element also works
const [children, setChildren] = createSignal<ResolvedJSXElement>([])

<Children get={setChildren}>
   <div></div>
   ...
</Children>

<Ref>

Get up-to-date reference to a single child element.

Import

import { Ref } from "@solid-primitives/refs";

How to use it

<Ref> accepts these properties:

• ref - Getter of current element (or undefined if not mounted)
• onMount - handle the child element getting mounted to the dom
• onUnmount - handle the child element getting unmounted from the dom

const [ref, setRef] = createSignal<Element | undefined>();

<Ref
  ref={setRef}
  onMount={el => console.log("Mounted", el)}
  onUnmount={el => console.log("Unmounted", el)}
>
  <Show when={show()}>
    <div>Hello</div>
  </Show>
</Ref>;

Providing generic Element type

<Ref<HTMLDivElement>
  ref={el => {...}} // HTMLDivElement | undefined
  onMount={el => {...}} // HTMLDivElement
  onUnmount={el => {...}} // HTMLDivElement
>
  <div>Hello</div>
</Ref>

<Refs>

Get up-to-date references of the multiple children elements.

Import

import { Refs } from "@solid-primitives/refs";

How to use it

<Refs> accepts these properties:

• refs - Getter of current array of elements
• added - Getter of added elements since the last change
• removed - Getter of removed elements since the last change
• onChange - handle children changes

const [refs, setRefs] = createSignal<Element[]>([]);

<Refs
  refs={setRefs}
  added={els => console.log("Added elements", els)}
  removed={els => console.log("Removed elements", els)}
  onChange={e => console.log(e)}
>
  <For each={my_list()}>{item => <div>{item}</div>}</For>
  <Show when={show()}>
    <div>Hello</div>
  </Show>
</Refs>;

Providing generic Element type

<Refs<HTMLDivElement>
  refs={els => {}} // HTMLDivElement[]
  added={els => {}} // HTMLDivElement[]
  removed={els => {}} // HTMLDivElement[]
  // { refs: HTMLDivElement[]; added: HTMLDivElement[]; removed: HTMLDivElement[] }
  onChange={e => {}}
>
  <div>Hello</div>
</Refs>

Demo

https://stackblitz.com/edit/solid-vite-unocss-bkbgap?file=index.tsx

(run npm start in the terminal)

Types

RefProps

Component properties with types for ref

interface RefProps<T extends Element> {
  ref?: T | ((el: T) => void);
}

ResolvedChildren

Type of resolved JSX elements provided by Solid's children helper.

type ResolvedChildren = ResolvedJSXElement | ResolvedJSXElement[];

Changelog

See CHANGELOG.md