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/2019/InstanceofOperator.js

@@ -0,0 +1,30 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+
+var $TypeError = require('es-errors/type');
+var isObject = require('es-object-atoms/isObject');
+
+var $hasInstance = GetIntrinsic('%Symbol.hasInstance%', true);
+
+var Call = require('./Call');
+var GetMethod = require('./GetMethod');
+var IsCallable = require('./IsCallable');
+var OrdinaryHasInstance = require('./OrdinaryHasInstance');
+var ToBoolean = require('./ToBoolean');
+
+// https://262.ecma-international.org/6.0/#sec-instanceofoperator
+
+module.exports = function InstanceofOperator(O, C) {
+	if (!isObject(O)) {
+		throw new $TypeError('Assertion failed: Type(O) is not Object');
+	}
+	var instOfHandler = $hasInstance ? GetMethod(C, $hasInstance) : void 0;
+	if (typeof instOfHandler !== 'undefined') {
+		return ToBoolean(Call(instOfHandler, C, [O]));
+	}
+	if (!IsCallable(C)) {
+		throw new $TypeError('`C` is not Callable');
+	}
+	return OrdinaryHasInstance(C, O);
+};