diff --git a/node/node-tests.ts b/node/node-tests.ts
index fd79f28f9d..bd19697f31 100644
--- a/node/node-tests.ts
+++ b/node/node-tests.ts
@@ -244,10 +244,21 @@ function bufferTests() {
         let index: number;
         index = buffer.indexOf("23");
         index = buffer.indexOf("23", 1);
+        index = buffer.indexOf("23", 1, "utf8");
         index = buffer.indexOf(23);
         index = buffer.indexOf(buffer);
     }
 
+    {
+        let buffer = new Buffer('123');
+        let index: number;
+        index = buffer.lastIndexOf("23");
+        index = buffer.lastIndexOf("23", 1);
+        index = buffer.lastIndexOf("23", 1, "utf8");
+        index = buffer.lastIndexOf(23);
+        index = buffer.lastIndexOf(buffer);
+    }
+
     // Imported Buffer from buffer module works properly
     {
         let b = new ImportedBuffer('123');
diff --git a/node/node.d.ts b/node/node.d.ts
index 750d273988..d86dac906c 100644
--- a/node/node.d.ts
+++ b/node/node.d.ts
@@ -503,8 +503,8 @@ interface NodeBuffer extends Uint8Array {
     writeDoubleLE(value: number, offset: number, noAssert?: boolean): number;
     writeDoubleBE(value: number, offset: number, noAssert?: boolean): number;
     fill(value: any, offset?: number, end?: number): this;
-    // TODO: encoding param
-    indexOf(value: string | number | Buffer, byteOffset?: number): number;
+    indexOf(value: string | number | Buffer, byteOffset?: number, encoding?: string): number;
+    lastIndexOf(value: string | number | Buffer, byteOffset?: number, encoding?: string): number;
     // TODO: entries
     // TODO: includes
     // TODO: keys