Index: frontend/node_modules/side-channel-map/index.js
===================================================================
--- frontend/node_modules/side-channel-map/index.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
+++ frontend/node_modules/side-channel-map/index.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
@@ -0,0 +1,68 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+var callBound = require('call-bound');
+var inspect = require('object-inspect');
+
+var $TypeError = require('es-errors/type');
+var $Map = GetIntrinsic('%Map%', true);
+
+/** @type {<K, V>(thisArg: Map<K, V>, key: K) => V} */
+var $mapGet = callBound('Map.prototype.get', true);
+/** @type {<K, V>(thisArg: Map<K, V>, key: K, value: V) => void} */
+var $mapSet = callBound('Map.prototype.set', true);
+/** @type {<K, V>(thisArg: Map<K, V>, key: K) => boolean} */
+var $mapHas = callBound('Map.prototype.has', true);
+/** @type {<K, V>(thisArg: Map<K, V>, key: K) => boolean} */
+var $mapDelete = callBound('Map.prototype.delete', true);
+/** @type {<K, V>(thisArg: Map<K, V>) => number} */
+var $mapSize = callBound('Map.prototype.size', true);
+
+/** @type {import('.')} */
+module.exports = !!$Map && /** @type {Exclude<import('.'), false>} */ function getSideChannelMap() {
+	/** @typedef {ReturnType<typeof getSideChannelMap>} Channel */
+	/** @typedef {Parameters<Channel['get']>[0]} K */
+	/** @typedef {Parameters<Channel['set']>[1]} V */
+
+	/** @type {Map<K, V> | undefined} */ var $m;
+
+	/** @type {Channel} */
+	var channel = {
+		assert: function (key) {
+			if (!channel.has(key)) {
+				throw new $TypeError('Side channel does not contain ' + inspect(key));
+			}
+		},
+		'delete': function (key) {
+			if ($m) {
+				var result = $mapDelete($m, key);
+				if ($mapSize($m) === 0) {
+					$m = void undefined;
+				}
+				return result;
+			}
+			return false;
+		},
+		get: function (key) { // eslint-disable-line consistent-return
+			if ($m) {
+				return $mapGet($m, key);
+			}
+		},
+		has: function (key) {
+			if ($m) {
+				return $mapHas($m, key);
+			}
+			return false;
+		},
+		set: function (key, value) {
+			if (!$m) {
+				// @ts-expect-error TS can't handle narrowing a variable inside a closure
+				$m = new $Map();
+			}
+			$mapSet($m, key, value);
+		}
+	};
+
+	// @ts-expect-error TODO: figure out why TS is erroring here
+	return channel;
+};