feat : merge mat

lib/material-poster.ts

@@ -0,0 +1,33 @@
+export type PosterMaterial = {
+  key: string;
+  amount: number;
+  name: string;
+  imageUrl: string | null;
+};
+
+export function mergePosterMaterials(materials: PosterMaterial[]): PosterMaterial[] {
+  const merged: PosterMaterial[] = [];
+  const indexByImageUrl = new Map<string, number>();
+
+  for (const material of materials) {
+    if (!material.imageUrl) {
+      merged.push(material);
+      continue;
+    }
+
+    const existingIndex = indexByImageUrl.get(material.imageUrl);
+    if (existingIndex === undefined) {
+      indexByImageUrl.set(material.imageUrl, merged.length);
+      merged.push(material);
+      continue;
+    }
+
+    const existing = merged[existingIndex];
+    merged[existingIndex] = {
+      ...existing,
+      amount: existing.amount + material.amount,
+    };
+  }
+
+  return merged;
+}