I have a question regarding reactive variable sharing between components. I have an example with checkboxes. Whenever only the sink checkbox is checked, I want to return a paragraph with a specific message. However, only the else statement is evaluated in component 2.

Maybe I have to use the store in svelte? I am not sure how to accomplish that.

A REPL can be found here: https://svelte.dev/repl/f2da2e91083f41098bd9b7c84ec199d2?version=3.49.0

The app component looks like this

<script>
    import Component2 from './Component2.svelte';
    
    let checked_sink = true;
    let checked_source = false;
    export let sink_source_checkbox = ["Sink"]
</script>

<label>
<input type=checkbox name="sink_source" value="Sink" bind:group={sink_source_checkbox} bind:checked={checked_sink}>
Sink
</label>
<label>
<input type=checkbox name="sink_source" value="Source" bind:group={sink_source_checkbox} bind:checked={checked_source}>
Source
</label>

<Component2/> 

checked 1: {checked_sink} <br/>
checked 2: {checked_source} <br/>
{JSON.stringify(sink_source_checkbox.toString())} 

And the 2nd component looks lik this

<script>
import sink_source_checkbox from './App.svelte';
</script>

{#if sink_source_checkbox.toString() === "Sink"}
    <p>
        It is only Sink
</p>
{:else}
<p>
    It is not only Sink
</p>
{/if}

>Solution :

Instead of the import export the variable from Component2 and pass it as a prop REPL

(There are probably various ways check for only ‘Sink’… And maybe you might reduce your example and just use the group binding without the parallel tracking of bind:checked. I changed that in the Repl…)

<script>
    export let checked
</script>

{#if checked.join() === "Sink"}
<p>
    It is only Sink
</p>
{:else}
<p>
    It is not only Sink
</p>
{/if}

In App.svelte

<Component2 checked={sink_source_checkbox}/>