fix: make flatpack diff friendly

.prettierignore

@@ -14,6 +14,7 @@ CHANGELOG.md
 examples/release-notes.md
 **/cspell-cache-flatpack.json
 **/cspell-cache-flatted.json
+**/.npm*.json
 coverage
 **/*.schema.json
 integration-tests/config/config.json

packages/flatpack-json/src/CompactStorage.mts

@@ -0,0 +1,13 @@
+import type { Flatpacked, FlatpackOptions, Serializable } from './types.mjs';
+
+export interface CompactStorageApi {
+    toJSON<V extends Serializable>(json: V): Flatpacked;
+}
+
+export abstract class CompactStorage implements CompactStorageApi {
+    readonly options?: FlatpackOptions | undefined;
+    constructor(options?: FlatpackOptions | undefined) {
+        this.options = options;
+    }
+    abstract toJSON<V extends Serializable>(json: V): Flatpacked;
+}