How to make a search filter in svelte

Question

I have two components that are very far away in the component tree and I have doubts about how to communicate between both. I have the search component, listItems and a store.

store.svelte

<script context="module" lang="ts">
 import type {Items} from '../../Models/Items.model';
 import { writable } from 'svelte/store';

 export const dataItems = writable<Items[]>([]);

  const filterInfo = (term:string) => {
     dataItems.update(item => {
           item.filter(x => {
                return x.name.toLowerCase().includes(term.toLowerCase())
                || x.description.toLowerCase().includes(term.toLowerCase());
           })
           return dataItems;
        })
    }*/


export const dispatcher = {filterInfo};

</script>

search component

<script lang="ts">
    import { dispatcher } from './ViewI/store.svelte';
    

    let value:any;

    const handleChange = () => {
     dispatcher.filterInfo(value)
    console.log(value)
     }
    
    
</script>

<Search>
 <input bind:value
 on:input={handleChange}>
</Search>

listItems component

import type {Items} from '../../Models/Items.model';
import {dataItems,dispatcher} from './store.svelte';

export let items:Items[] =[];
export let value:any;

$:filterItems = items;

$: {
  filterItems = $dataItems.filter((item:any) => {
    return item.name  || item.description
  });
  
  dispatcher.filterInfo(value);
 }



</script>

<main>
  
      {#each [...filterItems] as item }
           <CardItems
              name={item.name}
              description={user.description}
              id={item.id}
            /> 
           {/each}

</main>

The question is how to communicate both components with the value that you write in the input and make the filter.

Answer 1

You can accomplish this using a derived store. Here is a small example.

Set up three stores: term will hold the term being searched for, items will hold the full list of items, and filtered will be a derived store that contains the items that include the term. It will automatically be updated whenever term or items change.

// stores.js
import { writable, derived } from 'svelte/store';

export const term = writable('');
export const items = writable(['dog', 'cat', 'fish', 'iguana']);
export const filtered = derived(
    [term, items], 
    ([$term, $items]) => $items.filter(x => x.includes($term))
);

You can then use these stores across your application. Your Search component can set the term being searched for like so.

<!-- Search.svelte -->
<script>
    import {term} from './stores.js';
    let val = '';
    
    $: term.set(val);
</script>

<label for="searchInput">Search</label>
<input bind:value={val} type="text" id="searchInput">

When you call term.set(val), the derived store will automatically be updated. You can use this store in any component in your application.

<!-- ListItems.svelte -->
<script>
    import { filtered } from './stores.js';
</script>

<ul>
{#each $filtered as item}
    <li>{item}</li>
{/each}
</ul>

You can see a working example in the Svelte REPL.