Optional quantity formatter.

src/Formatters/OptionalQuantityFormatter.php

@@ -0,0 +1,37 @@
+<?php
+
+/**
+ * This file is part of web3.php package.
+ * 
+ * (c) Kuan-Cheng,Lai <alk03073135@gmail.com>
+ * 
+ * @author Peter Lai <alk03073135@gmail.com>
+ * @license MIT
+ */
+
+namespace Web3\Formatters;
+
+use InvalidArgumentException;
+use Web3\Utils;
+use Web3\Formatters\IFormatter;
+use Web3\Validators\TagValidator;
+
+class OptionalQuantityFormatter implements IFormatter
+{
+    /**
+     * format
+     * 
+     * @param mixed $value
+     * @return string
+     */
+    public static function format($value)
+    {
+        if (TagValidator::validate($value)) {
+            return $value;
+        }
+        $value = Utils::toString($value);
+        $bn = Utils::toBn($value);
+
+        return '0x' . $bn->toHex(true);
+    }
+}