fix: keep the text typed in the Sieve editor when the script refreshes (bulwarkmail/webmail#1162)

src/lib/sieve/__tests__/editor-seed.test.ts

@@ -0,0 +1,11 @@
+import { describe, expect, it } from 'vitest';
+import { seedsOnRender } from '../editor-seed';
+
+describe('seedsOnRender', () => {
+  it('seeds the Sieve editor when it opens, not when the script is refreshed while it is open (#1162)', () => {
+    expect(seedsOnRender(false, true)).toBe(true);
+    expect(seedsOnRender(true, true)).toBe(false);
+    expect(seedsOnRender(true, false)).toBe(false);
+    expect(seedsOnRender(false, false)).toBe(false);
+  });
+});

src/lib/sieve/editor-seed.ts

@@ -0,0 +1,8 @@
+/**
+ * Whether an editor sheet takes its content afresh: only when it opens. A
+ * new `content` while it is open (a store refresh) must not replace what the
+ * user typed (#1162).
+ */
+export function seedsOnRender(wasVisible: boolean, visible: boolean): boolean {
+  return visible && !wasVisible;
+}