Start implemention tagmove

ts/editor/Tag.svelte

@@ -49,6 +49,8 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         on:tagadd
         on:tagjoinprevious
         on:tagjoinnext
+        on:tagmoveprevious
+        on:tagmovenext
         on:mount={(event) => event.detail.input.focus()}
     />
 {:else}

ts/editor/TagEditor.svelte

@@ -88,6 +88,23 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         setPosition(length);
     }
 
+    function moveToPreviousTag(index: number): void {
+        if (index === 0 || tags.length === 1) {
+            return;
+        }
+
+        const before = tags.splice(index - 1, 1)[0];
+        tags.splice(index, 0, before);
+        tags = tags;
+    }
+
+    function moveToNextTag(index: number): void {
+        if (index === tags.length - 1 || tags.length === 1) {
+            return;
+        }
+        // TODO
+    }
+
     function appendTag(): void {
         const names = tags.map(getName);
         if (!names.includes(newName) && newName.length > 0) {
@@ -107,6 +124,10 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
             setPosition(popped.name.length);
         }
     }
+
+    function moveToLastTag(): void {
+        appendTag();
+    }
 </script>
 
 <StickyBottom>
@@ -132,6 +153,8 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
                             joinWithPreviousTag(index, detail.setPosition)}
                         on:tagjoinnext={({ detail }) =>
                             joinWithNextTag(index, detail.setPosition)}
+                        on:tagmoveprevious={() => moveToPreviousTag(index)}
+                        on:tagmovenext={() => moveToNextTag(index)}
                     />
                 {/each}
 
@@ -144,6 +167,7 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
                     on:tagadd={appendTag}
                     on:tagjoinprevious={({ detail }) =>
                         joinWithLastTag(detail.setPosition)}
+                    on:tagmoveprevious={moveToLastTag}
                 />
             </TagAutocomplete>
         </ButtonToolbar>

ts/editor/TagInput.svelte

@@ -11,6 +11,17 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
     const dispatch = createEventDispatcher();
 
+    function caretAtStart(): boolean {
+        return input.selectionStart === 0 && input.selectionEnd === 0;
+    }
+
+    function caretAtEnd(): boolean {
+        return (
+            input.selectionStart === input.value.length &&
+            input.selectionEnd === input.value.length
+        );
+    }
+
     function setPosition(position: number): void {
         setTimeout(() => input.setSelectionRange(position, position));
     }
@@ -21,7 +32,7 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     }
 
     function onBackspace(event: KeyboardEvent) {
-        if (input.selectionStart === 0 && input.selectionEnd === 0) {
+        if (caretAtStart()) {
             dispatch("tagjoinprevious", { setPosition });
             event.preventDefault();
         } else if (name.endsWith("::")) {
@@ -31,10 +42,7 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     }
 
     function onDelete(event: KeyboardEvent) {
-        if (
+        if (caretAtEnd()) {
-            input.selectionStart === input.value.length &&
-            input.selectionEnd === input.value.length
-        ) {
             dispatch("tagjoinnext", { setPosition });
             event.preventDefault();
         } else if (name.endsWith("::")) {
@@ -47,6 +55,12 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
         if (event.code === "Space") {
             name += "::";
             event.preventDefault();
+        } else if (event.code === "ArrowLeft" && caretAtStart()) {
+            dispatch("tagmoveprevious");
+            event.preventDefault();
+        } else if (event.code === "ArrowRight" && caretAtEnd()) {
+            dispatch("tagmovenext");
+            event.preventDefault();
         } else if (event.code === "Backspace") {
             onBackspace(event);
         } else if (event.code === "Delete") {