Fix indexOf tests

node/_tools/config.json

@@ -18,6 +18,7 @@
       "test-buffer-arraybuffer.js",
       "test-buffer-bytelength.js",
       "test-buffer-from.js",
+      "test-buffer-indexof.js",
       "test-dns-lookup.js",
       "test-dns.js",
       "test-event-emitter-errors.js",

node/_tools/suites/parallel/test-buffer-indexof.js

@@ -601,6 +601,8 @@ pattern = reallyLong.slice(0, 2000000);  // first 2/5ths.
 assert.strictEqual(reallyLong.lastIndexOf(pattern), 0);
 
 // Test truncation of Number arguments to uint8
+// TODO(Soremwar)
+// Enable once multi byte number search is available
 // {
 //   const buf = Buffer.from('this is a test');
 //   assert.strictEqual(buf.indexOf(0x6973), 3);

node/internal_binding/buffer.ts

@@ -1,6 +1,18 @@
 import { Encodings } from "./_node.ts";
 import { indexOf } from "../../bytes/mod.ts";
 
+export function numberToBytes(n: number): Uint8Array {
+  if (n === 0) return new Uint8Array([0]);
+
+  const bytes = [];
+  bytes.unshift(n & 255);
+  while (n >= 256) {
+    n = n >>> 8;
+    bytes.unshift(n & 255);
+  }
+  return new Uint8Array(bytes);
+}
+
 // TODO(Soremwar)
 // Check if offset or buffer can be transform in order to just use std's lastIndexOf directly
 // This implementation differs from std's lastIndexOf in the fact that
@@ -88,24 +100,26 @@ function indexOfBuffer(
   return indexOf(targetBuffer, buffer, byteOffset);
 }
 
+// TODO(Soremwar)
+// Node's implementation is a very obscure algorithm that I haven't been able to crack just yet
 function indexOfNumber(
   targetBuffer: Uint8Array,
   number: number,
   byteOffset: number,
   forwardDirection: boolean,
 ) {
-  if (!forwardDirection) {
-    return Uint8Array.prototype.lastIndexOf.call(
-      targetBuffer,
-      number,
-      byteOffset,
-    );
+  const bytes = numberToBytes(number);
+
+  if (bytes.length > 1) {
+    throw new Error("Multi byte number search is not supported");
   }
 
-  return Uint8Array.prototype.indexOf.call(
+  return indexOfBuffer(
     targetBuffer,
-    number,
+    numberToBytes(number),
     byteOffset,
+    Encodings.UTF8,
+    forwardDirection,
   );
 }