Index: frontend/node_modules/is-callable/index.js
===================================================================
--- frontend/node_modules/is-callable/index.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
+++ frontend/node_modules/is-callable/index.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
@@ -0,0 +1,101 @@
+'use strict';
+
+var fnToStr = Function.prototype.toString;
+var reflectApply = typeof Reflect === 'object' && Reflect !== null && Reflect.apply;
+var badArrayLike;
+var isCallableMarker;
+if (typeof reflectApply === 'function' && typeof Object.defineProperty === 'function') {
+	try {
+		badArrayLike = Object.defineProperty({}, 'length', {
+			get: function () {
+				throw isCallableMarker;
+			}
+		});
+		isCallableMarker = {};
+		// eslint-disable-next-line no-throw-literal
+		reflectApply(function () { throw 42; }, null, badArrayLike);
+	} catch (_) {
+		if (_ !== isCallableMarker) {
+			reflectApply = null;
+		}
+	}
+} else {
+	reflectApply = null;
+}
+
+var constructorRegex = /^\s*class\b/;
+var isES6ClassFn = function isES6ClassFunction(value) {
+	try {
+		var fnStr = fnToStr.call(value);
+		return constructorRegex.test(fnStr);
+	} catch (e) {
+		return false; // not a function
+	}
+};
+
+var tryFunctionObject = function tryFunctionToStr(value) {
+	try {
+		if (isES6ClassFn(value)) { return false; }
+		fnToStr.call(value);
+		return true;
+	} catch (e) {
+		return false;
+	}
+};
+var toStr = Object.prototype.toString;
+var objectClass = '[object Object]';
+var fnClass = '[object Function]';
+var genClass = '[object GeneratorFunction]';
+var ddaClass = '[object HTMLAllCollection]'; // IE 11
+var ddaClass2 = '[object HTML document.all class]';
+var ddaClass3 = '[object HTMLCollection]'; // IE 9-10
+var hasToStringTag = typeof Symbol === 'function' && !!Symbol.toStringTag; // better: use `has-tostringtag`
+
+var isIE68 = !(0 in [,]); // eslint-disable-line no-sparse-arrays, comma-spacing
+
+var isDDA = function isDocumentDotAll() { return false; };
+if (typeof document === 'object') {
+	// Firefox 3 canonicalizes DDA to undefined when it's not accessed directly
+	var all = document.all;
+	if (toStr.call(all) === toStr.call(document.all)) {
+		isDDA = function isDocumentDotAll(value) {
+			/* globals document: false */
+			// in IE 6-8, typeof document.all is "object" and it's truthy
+			if ((isIE68 || !value) && (typeof value === 'undefined' || typeof value === 'object')) {
+				try {
+					var str = toStr.call(value);
+					return (
+						str === ddaClass
+						|| str === ddaClass2
+						|| str === ddaClass3 // opera 12.16
+						|| str === objectClass // IE 6-8
+					) && value('') == null; // eslint-disable-line eqeqeq
+				} catch (e) { /**/ }
+			}
+			return false;
+		};
+	}
+}
+
+module.exports = reflectApply
+	? function isCallable(value) {
+		if (isDDA(value)) { return true; }
+		if (!value) { return false; }
+		if (typeof value !== 'function' && typeof value !== 'object') { return false; }
+		try {
+			reflectApply(value, null, badArrayLike);
+		} catch (e) {
+			if (e !== isCallableMarker) { return false; }
+		}
+		return !isES6ClassFn(value) && tryFunctionObject(value);
+	}
+	: function isCallable(value) {
+		if (isDDA(value)) { return true; }
+		if (!value) { return false; }
+		if (typeof value !== 'function' && typeof value !== 'object') { return false; }
+		if (hasToStringTag) { return tryFunctionObject(value); }
+		if (isES6ClassFn(value)) { return false; }
+		var strClass = toStr.call(value);
+		if (strClass !== fnClass && strClass !== genClass && !(/^\[object HTML/).test(strClass)) { return false; }
+		return tryFunctionObject(value);
+	};