diff --git a/lib/source-map-consumer.js b/lib/source-map-consumer.js
index 17ef92b1..f5f96460 100644
--- a/lib/source-map-consumer.js
+++ b/lib/source-map-consumer.js
@@ -283,7 +283,7 @@ class BasicSourceMapConsumer extends SourceMapConsumer {
    * @returns BasicSourceMapConsumer
    */
   static fromSourceMap(aSourceMap, aSourceMapURL) {
-    return new BasicSourceMapConsumer(aSourceMap.toString());
+    return new BasicSourceMapConsumer(aSourceMap.toString(), aSourceMapURL);
   }
 
   get sources() {
diff --git a/source-map.d.ts b/source-map.d.ts
index 45646052..119962f6 100644
--- a/source-map.d.ts
+++ b/source-map.d.ts
@@ -381,7 +381,7 @@ export class SourceMapGenerator {
 }
 
 export class SourceNode {
-  children: SourceNode[];
+  children: (SourceNode | string)[];
   sourceContents: any;
   line: number;
   column: number;