diff --git a/declarations.d.ts b/declarations.d.ts
index a3066e990..beb84bef9 100644
--- a/declarations.d.ts
+++ b/declarations.d.ts
@@ -246,10 +246,20 @@ declare module "@webassemblyjs/ast" {
 declare module "webpack-sources" {
 	export type MapOptions = { columns?: boolean; module?: boolean };
 
+	export type RawSourceMap = {
+		version: number;
+		sources: string[];
+		names: string[];
+		sourceRoot?: string;
+		sourcesContent?: string[];
+		mappings: string;
+		file: string;
+	};
+
 	export abstract class Source {
 		size(): number;
 
-		map(options?: MapOptions): Object;
+		map(options?: MapOptions): RawSourceMap | null;
 
 		sourceAndMap(options?: MapOptions): {
 			source: string | Buffer;
diff --git a/types.d.ts b/types.d.ts
index 78da415cf..44cd3b9f8 100644
--- a/types.d.ts
+++ b/types.d.ts
@@ -9358,6 +9358,15 @@ declare class RawSource extends Source {
 	constructor(source: string | Buffer, convertToString?: boolean);
 	isBuffer(): boolean;
 }
+declare interface RawSourceMap {
+	version: number;
+	sources: string[];
+	names: string[];
+	sourceRoot?: string;
+	sourcesContent?: string[];
+	mappings: string;
+	file: string;
+}
 declare class ReadFileCompileWasmPlugin {
 	constructor(options?: any);
 	options: any;
@@ -11104,7 +11113,7 @@ declare abstract class SortableSet<T> extends Set<T> {
 declare class Source {
 	constructor();
 	size(): number;
-	map(options?: MapOptions): Object;
+	map(options?: MapOptions): null | RawSourceMap;
 	sourceAndMap(options?: MapOptions): { source: string | Buffer; map: Object };
 	updateHash(hash: Hash): void;
 	source(): string | Buffer;