Initial commit: Developer Tools MVP with visual editor

- Complete React app with 7 developer tools
- JSON Tool with visual structured editor
- Serialize Tool with visual structured editor
- URL, Base64, CSV/JSON, Beautifier, Diff tools
- Responsive navigation with dropdown menu
- Dark/light mode toggle
- Mobile-responsive design with sticky header
- All tools working with copy/paste functionality

node_modules/es-abstract/2023/thisBigIntValue.js

@@ -0,0 +1,18 @@
+'use strict';
+
+var callBound = require('call-bound');
+
+var $SyntaxError = require('es-errors/syntax');
+var $bigIntValueOf = callBound('BigInt.prototype.valueOf', true);
+
+// https://262.ecma-international.org/11.0/#sec-thisbigintvalue
+
+module.exports = function thisBigIntValue(value) {
+	if (typeof value === 'bigint') {
+		return value;
+	}
+	if (!$bigIntValueOf) {
+		throw new $SyntaxError('BigInt is not supported');
+	}
+	return $bigIntValueOf(value);
+};