diff --git a/package.json b/package.json
index b13cb9a..523c704 100644
--- a/package.json
+++ b/package.json
@@ -6,11 +6,11 @@
 	"main": "./dist/index.js",
 	"types": "./src/index.ts",
 	"scripts": {
-		"build": "tsup",
+		"build": "tsup && tsc --declaration --emitDeclarationOnly --declarationDir dist --noEmit false",
 		"lint": "eslint src --fix",
 		"prettier": "prettier --write src/**/*.ts",
 		"start": "npm run build && node --trace-warnings --enable-source-maps .",
-		"test": "eslint src && tsc --noEmit && tsup _test.ts --format esm && node dist/_test.mjs",
+		"test": "eslint src && tsc && tsup _test.ts --format esm && node dist/_test.mjs",
 		"postinstall": "npm run build"
 	},
 	"repository": {
diff --git a/src/structures/Tassa.ts b/src/structures/Tassa.ts
index e77ce1b..5f0d4eb 100644
--- a/src/structures/Tassa.ts
+++ b/src/structures/Tassa.ts
@@ -49,8 +49,14 @@ export class Tassa extends Base<TassaData> {
 	patch(data: Data) {
 		if (this.isJson(data)) {
 			this.handleJson(data);
-			this.dataCreazione = data.dataCreazione && new Date(data.dataCreazione);
-			this.dataPagamento = data.dataPagamento && new Date(data.dataPagamento);
+			this.dataCreazione =
+				data.dataCreazione === undefined
+					? undefined
+					: new Date(data.dataCreazione);
+			this.dataPagamento =
+				data.dataPagamento === undefined
+					? undefined
+					: new Date(data.dataPagamento);
 			this.scadenza = new Date(data.scadenza);
 		} else {
 			if (data.dataCreazione != null)
diff --git a/src/types/general.ts b/src/types/general.ts
index ed04651..2419819 100644
--- a/src/types/general.ts
+++ b/src/types/general.ts
@@ -97,26 +97,31 @@ export type ClientOptions = Partial<
 		} | null;
 	}
 >;
-export type Jsonify<T, N extends boolean = false, D extends boolean = true> = [
-	T,
-	D
-] extends [
-	{
-		toJSON(): infer J;
-	},
-	true
-]
-	? Jsonify<J, false, false>
+export type Jsonify<T, D extends boolean = true> = D extends true
+	? Jsonify<
+			T extends {
+				toJSON(): infer J;
+			}
+				? J
+				: T,
+			false
+	  >
 	: T extends boolean | number | string | null
 	? T
 	: T extends bigint
 	? never
 	: T extends symbol | ((...args: any[]) => any) | undefined
-	? N extends true
-		? never
-		: undefined
+	? undefined
+	: T extends (infer A)[]
+	? Jsonify<A>[]
 	: {
-			[K in keyof T]: Jsonify<T[K], true>;
+			[K in keyof T as T[K] extends
+				| bigint
+				| symbol
+				| ((...args: any[]) => any)
+				| undefined
+				? never
+				: K]: Jsonify<T[K]>;
 	  };
 export type LoginLink = {
 	url: string;
diff --git a/tsconfig.json b/tsconfig.json
index 2ffb7c8..1e5b637 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -2,12 +2,14 @@
 	"include": ["src/**/*"],
 	"extends": "@tsconfig/node18/tsconfig.json",
 	"compilerOptions": {
-		"moduleResolution": "node",
 		"allowSyntheticDefaultImports": true,
 		"allowUnreachableCode": false,
 		"alwaysStrict": true,
 		"esModuleInterop": true,
 		"isolatedModules": true,
+		"module": "ESNext",
+		"moduleResolution": "node",
+		"noEmit": true,
 		"noFallthroughCasesInSwitch": true,
 		"noImplicitAny": true,
 		"noImplicitReturns": true,
@@ -17,7 +19,6 @@
 		"outDir": "dist",
 		"pretty": true,
 		"resolveJsonModule": true,
-		"sourceMap": true,
-		"module": "ESNext"
+		"sourceMap": true
 	}
 }
diff --git a/tsup.config.ts b/tsup.config.ts
index 329eb2e..33afe66 100644
--- a/tsup.config.ts
+++ b/tsup.config.ts
@@ -10,7 +10,6 @@ const options: Options = {
 	minify: true,
 	keepNames: true,
 	sourcemap: true,
-	dts: true,
 };
 
 export default defineConfig(options);