Synchronize primitive-typed Svelte stores across a simple WebSocket connection.
This was originally designed to allow touch panels to use Svelte with any backend.
Initialization
import { initialize } from "svelte-websocket-stores/websocket";
initialize({
server_address: "192.168.0.64",
local_scope: "tp1"
});
Write-only example
<script>
import { booleans } from "svelte-websocket-stores/store";
let pressStore = booleans.get("myCoolButton.press");
function press() {
$pressStore = true;
}
function release() {
$pressStore = false;
}
</script>
<button
on:pointerdown={press}
on:pointerup={release}
on:pointerout={release}>
<slot />
</button>
Read-only exmaple
<script>
import { numbers } from "svelte-websocket-stores/store";
let sizeStore = numbers.get("myList.size");
</script>
<div>
{#each { length: $sizeStore } as _, index}
<slot />
{/each}
</div>
All communication between a server and this library is over WebSocket.
All WebSocket messages are interpreted as JSON objects.
The message object is defined as:
type Message = {
scope: string,
id: string,
type: string,
value: boolean | number | string,
}
The field scope
identifies the scope of the client it comes from and limits which clients receive it when coming from the server.
The field type
determines how the value
field is interpreted as well as which of the tables (booleans, numbers, or strings) the id
field will be indexing into.
scope
field is checked if it is global ("global") or matches the client's local scope (for example "tp1"). If it does not match, the message is discarded.type
field is switched on with the cases "boolean"
, "number"
, and "string"
. If there is no match, the message is discarded.id
field from the dictionary holding the respectively typed stores.value
field, cast to its respective type.type
field is switched on with the cases "boolean"
, "number"
, and "string"
. If there is no match, the message is discarded.scope
and id
fields from the dictionary holding the respectively typed variables.value
field, cast to its respective type.[^1]: This is the behavior expected by this WebSocket client