1 files changed, 124 insertions, 0 deletions
diff --git a/school/node_modules/side-channel/index.js b/school/node_modules/side-channel/index.js
new file mode 100644
index 0000000..f1c4826
--- /dev/null
+++ b/school/node_modules/side-channel/index.js
@@ -0,0 +1,124 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+var callBound = require('call-bind/callBound');
+var inspect = require('object-inspect');
+
+var $TypeError = GetIntrinsic('%TypeError%');
+var $WeakMap = GetIntrinsic('%WeakMap%', true);
+var $Map = GetIntrinsic('%Map%', true);
+
+var $weakMapGet = callBound('WeakMap.prototype.get', true);
+var $weakMapSet = callBound('WeakMap.prototype.set', true);
+var $weakMapHas = callBound('WeakMap.prototype.has', true);
+var $mapGet = callBound('Map.prototype.get', true);
+var $mapSet = callBound('Map.prototype.set', true);
+var $mapHas = callBound('Map.prototype.has', true);
+
+/*
+ * This function traverses the list returning the node corresponding to the
+ * given key.
+ *
+ * That node is also moved to the head of the list, so that if it's accessed
+ * again we don't need to traverse the whole list. By doing so, all the recently
+ * used nodes can be accessed relatively quickly.
+ */
+var listGetNode = function (list, key) { // eslint-disable-line consistent-return
+	for (var prev = list, curr; (curr = prev.next) !== null; prev = curr) {
+		if (curr.key === key) {
+			prev.next = curr.next;
+			curr.next = list.next;
+			list.next = curr; // eslint-disable-line no-param-reassign
+			return curr;
+		}
+	}
+};
+
+var listGet = function (objects, key) {
+	var node = listGetNode(objects, key);
+	return node && node.value;
+};
+var listSet = function (objects, key, value) {
+	var node = listGetNode(objects, key);
+	if (node) {
+		node.value = value;
+	} else {
+		// Prepend the new node to the beginning of the list
+		objects.next = { // eslint-disable-line no-param-reassign
+			key: key,
+			next: objects.next,
+			value: value
+		};
+	}
+};
+var listHas = function (objects, key) {
+	return !!listGetNode(objects, key);
+};
+
+module.exports = function getSideChannel() {
+	var $wm;
+	var $m;
+	var $o;
+	var channel = {
+		assert: function (key) {
+			if (!channel.has(key)) {
+				throw new $TypeError('Side channel does not contain ' + inspect(key));
+			}
+		},
+		get: function (key) { // eslint-disable-line consistent-return
+			if ($WeakMap && key && (typeof key === 'object' || typeof key === 'function')) {
+				if ($wm) {
+					return $weakMapGet($wm, key);
+				}
+			} else if ($Map) {
+				if ($m) {
+					return $mapGet($m, key);
+				}
+			} else {
+				if ($o) { // eslint-disable-line no-lonely-if
+					return listGet($o, key);
+				}
+			}
+		},
+		has: function (key) {
+			if ($WeakMap && key && (typeof key === 'object' || typeof key === 'function')) {
+				if ($wm) {
+					return $weakMapHas($wm, key);
+				}
+			} else if ($Map) {
+				if ($m) {
+					return $mapHas($m, key);
+				}
+			} else {
+				if ($o) { // eslint-disable-line no-lonely-if
+					return listHas($o, key);
+				}
+			}
+			return false;
+		},
+		set: function (key, value) {
+			if ($WeakMap && key && (typeof key === 'object' || typeof key === 'function')) {
+				if (!$wm) {
+					$wm = new $WeakMap();
+				}
+				$weakMapSet($wm, key, value);
+			} else if ($Map) {
+				if (!$m) {
+					$m = new $Map();
+				}
+				$mapSet($m, key, value);
+			} else {
+				if (!$o) {
+					/*
+					 * Initialize the linked list as an empty node, so that we don't have
+					 * to special-case handling of the first node: we can always refer to
+					 * it as (previous node).next, instead of something like (list).head
+					 */
+					$o = { key: {}, next: null };
+				}
+				listSet($o, key, value);
+			}
+		}
+	};
+	return channel;
+};