[Chat input] Fix asian keyboards (#789)

src/lib/components/chat/ChatInput.svelte

@@ -11,6 +11,7 @@
 
 	let innerWidth = 0;
 	let textareaElement: HTMLTextAreaElement;
+	let isCompositionOn = false;
 
 	const dispatch = createEventDispatcher<{ submit: void }>();
 
@@ -19,7 +20,7 @@
 
 	function handleKeydown(event: KeyboardEvent) {
 		// submit on enter
-		if (event.key === "Enter" && !event.shiftKey) {
+		if (event.key === "Enter" && !event.shiftKey && !isCompositionOn) {
 			event.preventDefault();
 			dispatch("submit"); // use a custom event instead of `event.target.form.requestSubmit()` as it does not work on Safari 14
 		}
@@ -50,6 +51,8 @@
 		bind:this={textareaElement}
 		{disabled}
 		on:keydown={handleKeydown}
+		on:compositionstart={() => (isCompositionOn = true)}
+		on:compositionend={() => (isCompositionOn = false)}
 		on:keypress
 		{placeholder}
 	/>