carbon-components-svelte/src/MultiSelect/MultiSelect.svelte

<script>
  /**
   * Set the multiselect items
   * @type {MultiSelectItem[]} [items=[]]
   */
  export let items = [];

  /**
   * Override the display of a multiselect item
   * @type {(item: MultiSelectItem) => string} [itemToString = (item: MultiSelectItem) =>  MultiSelectItemText | MultiSelectItemId]
   */
  export let itemToString = (item) => item.text || item.id;

  /**
   * Set the selected ids
   * @type {MultiSelectItemId[]} [selectedIds=[]]
   */
  export let selectedIds = [];

  /**
   * Specify the multiselect value
   * @type {string} [value=""]
   */
  export let value = "";

  /**
   * Set the size of the combobox
   * @type {"sm" | "lg" | "xl"} [size]
   */
  export let size = undefined;

  /**
   * Specify the type of multiselect
   * @type {"default" | "inline"} [type="default"]
   */
  export let type = "default";

  /**
   * Specify the selection feedback after selecting items
   * @type {"top" | "fixed" | "top-after-reopen"} [selectionFeedback="top-after-reopen"]
   */
  export let selectionFeedback = "top-after-reopen";

  /**
   * Set to `true` to disable the dropdown
   * @type {boolean} [disabled=false]
   */
  export let disabled = false;

  /**
   * Set to `true` to filter items
   * @type {boolean} [filterable=false]
   */
  export let filterable = false;

  /**
   * Override the filtering logic
   * The default filtering is an exact string comparison
   * @type {(item: MultiSelectItem, value: string) => string} [filterItem = (item: MultiSelectItem, value: string) => string]
   */
  export let filterItem = (item, value) =>
    item.text.toLowerCase().includes(value.toLowerCase());

  /**
   * Set to `true` to open the dropdown
   * @type {boolean} [open=false]
   */
  export let open = false;

  /**
   * Set to `true` to enable the light variant
   * @type {boolean} [light=false]
   */
  export let light = false;

  /**
   * Specify the locale
   * @type {string} [locale="en"]
   */
  export let locale = "en";

  /**
   * Specify the placeholder text
   * @type {string} [placeholder=""]
   */
  export let placeholder = "";

  /**
   * Override the sorting logic
   * The default sorting compare the item text value
   * @type {(a: MultiSelectItem, b: MultiSelectItem) => MultiSelectItem} [sortItem = (a: MultiSelectItem, b: MultiSelectItem) => MultiSelectItem]
   */
  export let sortItem = (a, b) =>
    a.text.localeCompare(b.text, locale, { numeric: true });

  /**
   * Override the default translation ids
   * @type {(id: any) => string} [translateWithId]
   */
  export let translateWithId = undefined;

  /**
   * Specify the title text
   * @type {string} [titleText=""]
   */
  export let titleText = "";

  /**
   * Set to `true` to pass the item to `itemToString` in the checkbox
   * @type {boolean} [useTitleInItem=false]
   */
  export let useTitleInItem = false;

  /**
   * Set to `true` to indicate an invalid state
   * @type {boolean} [invalid=false]
   */
  export let invalid = false;

  /**
   * Specify the invalid state text
   * @type {string} [invalidText=""]
   */
  export let invalidText = "";

  /**
   * Specify the helper text
   * @type {string} [helperText=""]
   */
  export let helperText = "";

  /**
   * Specify the list box label
   * @type {string} [label]
   */
  export let label = "";

  /**
   * Set an id for the list box component
   * @type {string} [id]
   */
  export let id = "ccs-" + Math.random().toString(36);

  /**
   * Specify a name attribute for the select
   * @type {string} [name]
   */
  export let name = undefined;

  /**
   * @typedef {string} MultiSelectItemId
   * @typedef {string} MultiSelectItemText
   * @typedef {{ id: MultiSelectItemId; text: MultiSelectItemText; }} MultiSelectItem
   */

  import { afterUpdate, setContext } from "svelte";
  import WarningFilled16 from "carbon-icons-svelte/lib/WarningFilled16";
  import { Checkbox } from "../Checkbox";
  import {
    ListBox,
    ListBoxField,
    ListBoxMenu,
    ListBoxMenuIcon,
    ListBoxMenuItem,
    ListBoxSelection,
  } from "../ListBox";

  let multiSelectRef = null;
  let fieldRef = null;
  let selectionRef = null;
  let inputRef = null;

  $: inputValue = "";
  $: initialSorted = false;
  $: highlightedIndex = -1;
  $: prevChecked = [];

  setContext("MultiSelect", {
    declareRef: ({ key, ref }) => {
      switch (key) {
        case "field":
          fieldRef = ref;
          break;
        case "selection":
          selectionRef = ref;
          break;
      }
    },
  });

  function change(direction) {
    let index = highlightedIndex + direction;

    if (index < 0) {
      index = items.length - 1;
    } else if (index >= items.length) {
      index = 0;
    }

    highlightedIndex = index;
  }

  function sort() {
    return [
      ...(checked.length > 1 ? checked.sort(sortItem) : checked),
      ...unchecked.sort(sortItem),
    ];
  }

  afterUpdate(() => {
    if (checked.length !== prevChecked.length) {
      if (selectionFeedback === "top") {
        sortedItems = sort();
      }
      prevChecked = checked;
      selectedIds = checked.map(({ id }) => id);
    }

    if (!open) {
      if (!initialSorted || selectionFeedback !== "fixed") {
        sortedItems = sort();
        initialSorted = true;
      }

      highlightedIndex = -1;
      inputValue = "";
    }

    items = sortedItems;
  });

  $: menuId = `menu-${id}`;
  $: inline = type === "inline";
  $: ariaLabel = $$props["aria-label"] || "Choose an item";
  $: sortedItems = items.map((item) => ({
    ...item,
    checked: selectedIds.includes(item.id),
  }));
  $: checked = sortedItems.filter(({ checked }) => checked);
  $: unchecked = sortedItems.filter(({ checked }) => !checked);
  $: filteredItems = sortedItems.filter((item) => filterItem(item, value));
  $: highlightedId = sortedItems[highlightedIndex]
    ? sortedItems[highlightedIndex].id
    : undefined;
  $: value = inputValue;
</script>

<svelte:body
  on:click={({ target }) => {
    if (open && multiSelectRef && !multiSelectRef.contains(target)) {
      open = false;
    }
  }} />

<div
  bind:this={multiSelectRef}
  class:bx--multi-select__wrapper={true}
  class:bx--list-box__wrapper={true}
  class:bx--multi-select__wrapper--inline={inline}
  class:bx--list-box__wrapper--inline={inline}
  class:bx--multi-select__wrapper--inline--invalid={inline && invalid}
  {...$$restProps}>
  {#if titleText}
    <label for={id} class:bx--label={true} class:bx--label--disabled={disabled}>
      {titleText}
    </label>
  {/if}
  {#if !inline && helperText}
    <div
      class:bx--form__helper-text={true}
      class:bx--form__helper-text--disabled={disabled}>
      {helperText}
    </div>
  {/if}
  <ListBox
    aria-label={ariaLabel}
    {id}
    {disabled}
    {invalid}
    {invalidText}
    {open}
    {light}
    {size}
    class="bx--multi-select {filterable && 'bx--combo-box'}
    {filterable && 'bx--multi-select--filterable'}
    {invalid && 'bx--multi-select--invalid'}
    {inline && 'bx--multi-select--inline'}
    {checked.length > 0 && 'bx--multi-select--selected'}">
    {#if invalid}
      <WarningFilled16 class="bx--list-box__invalid-icon" />
    {/if}
    <ListBoxField
      role="button"
      tabindex="0"
      aria-expanded={open}
      on:click={() => {
        if (filterable) {
          open = true;
          inputRef.focus();
        } else {
          open = !open;
        }
      }}
      on:keydown={({ key }) => {
        if (filterable) {
          return;
        }
        if (key === ' ') {
          open = !open;
        } else if (key === 'Tab') {
          if (selectionRef && checked.length > 0) {
            selectionRef.focus();
          } else {
            open = false;
            fieldRef.blur();
          }
        } else if (key === 'ArrowDown') {
          change(1);
        } else if (key === 'ArrowUp') {
          change(-1);
        } else if (key === 'Enter') {
          if (highlightedIndex > -1) {
            sortedItems[highlightedIndex].checked = !sortedItems[highlightedIndex].checked;
          }
        }
      }}
      on:blur={({ relatedTarget }) => {
        if (relatedTarget && relatedTarget.getAttribute('role') !== 'button') {
          fieldRef.focus();
        }
      }}
      {id}
      {disabled}
      {translateWithId}>
      {#if checked.length > 0}
        <ListBoxSelection
          selectionCount={checked.length}
          on:clear={() => {
            sortedItems = sortedItems.map((item) => ({
              ...item,
              checked: false,
            }));
            fieldRef.blur();
          }}
          {translateWithId}
          {disabled} />
      {/if}
      {#if filterable}
        <input
          bind:this={inputRef}
          role="combobox"
          tabindex="0"
          autocomplete="off"
          aria-autocomplete="list"
          aria-expanded={open}
          aria-activedescendant={highlightedId}
          aria-disabled={disabled}
          aria-controls={menuId}
          class:bx--text-input={true}
          class:bx--text-input--empty={inputValue === ''}
          on:input={({ target }) => {
            inputValue = target.value;
          }}
          on:keydown
          on:keydown|stopPropagation={({ key }) => {
            if (key === 'Enter') {
              if (highlightedIndex > -1) {
                sortedItems[highlightedIndex].checked = !sortedItems[highlightedIndex].checked;
              }
            } else if (key === 'Tab') {
              open = false;
            } else if (key === 'ArrowDown') {
              change(1);
            } else if (key === 'ArrowUp') {
              change(-1);
            }
          }}
          on:focus
          on:blur
          on:blur={({ relatedTarget }) => {
            if (relatedTarget && relatedTarget.getAttribute('role') !== 'button') {
              inputRef.focus();
            }
          }}
          {disabled}
          {placeholder}
          {id}
          {name}
          value={inputValue} />
        {#if invalid}
          <WarningFilled16 class="bx--list-box__invalid-icon" />
        {/if}
        {#if inputValue}
          <ListBoxSelection
            on:clear={() => {
              inputValue = '';
              open = false;
            }}
            {translateWithId}
            {disabled}
            {open} />
        {/if}
        <ListBoxMenuIcon
          on:click={() => {
            open = !open;
          }}
          {translateWithId}
          {open} />
      {/if}
      {#if !filterable}
        <span class="bx--list-box__label">{label}</span>
        <ListBoxMenuIcon {open} {translateWithId} />
      {/if}
    </ListBoxField>
    {#if open}
      <ListBoxMenu aria-label={ariaLabel} {id}>
        {#each filterable ? filteredItems : sortedItems as item, i (item.id || i)}
          <ListBoxMenuItem
            id={item.id}
            active={item.checked}
            highlighted={highlightedIndex === i}
            on:click={() => {
              sortedItems = sortedItems.map((_) =>
                _.id === item.id ? { ..._, checked: !_.checked } : _
              );
              fieldRef.focus();
            }}
            on:mouseenter={() => {
              highlightedIndex = i;
            }}>
            <Checkbox
              readonly
              tabindex="-1"
              id="checkbox-{item.id}"
              title={useTitleInItem ? itemToString(item) : undefined}
              name={itemToString(item)}
              labelText={itemToString(item)}
              checked={item.checked}
              {disabled} />
          </ListBoxMenuItem>
        {/each}
      </ListBoxMenu>
    {/if}
  </ListBox>
</div>