diff --git a/source-list-map/index.d.ts b/source-list-map/index.d.ts
index c6cfb0ac45..2cde4e5839 100644
--- a/source-list-map/index.d.ts
+++ b/source-list-map/index.d.ts
@@ -49,9 +49,9 @@ export class SourceNode {
 }
 
 export class SourceListMap {
-    children: (SourceNode | CodeNode | SourceListMap)[];
+    children: (SourceNode | CodeNode)[];
 
-    constructor(generatedCode: (SourceNode | CodeNode | SourceListMap)[]);
+    constructor(generatedCode: (SourceNode | CodeNode)[]);
     constructor(
         generatedCode?: string | SourceNode | CodeNode | SourceListMap,
         source?: string,
@@ -84,9 +84,8 @@ export class SourceListMap {
 
 export function fromStringWithSourceMap(
     code: string, map: {
-        sources: any;
-        sourcesContent: any;
-        mappings: any;
+        sources: (string | SourceNode | CodeNode) [];
+        sourcesContent: string[];
+        mappings: string;
     }
 ): SourceListMap;
-
diff --git a/source-list-map/source-list-map-tests.ts b/source-list-map/source-list-map-tests.ts
index 75341740be..5fe932efc5 100644
--- a/source-list-map/source-list-map-tests.ts
+++ b/source-list-map/source-list-map-tests.ts
@@ -13,9 +13,9 @@ node.mapGeneratedCode(function (code) {
 })
 
 slm.fromStringWithSourceMap('hello', {
-    sources: null,
-    sourcesContent: null,
-    mappings: null
+    sources: [node, new slm.CodeNode('hello')],
+    sourcesContent: ['hi'],
+    mappings: 'null'
 });
 
 const snode = new slm.SourceNode('hi', 'i\'am', 'e-cloud');