Updating Chai externs with the exists() and notExists() functions.
See the definitions:
@@ -392,6 +392,18 @@ assert.isNotNull = function(value, message) {}
*/
assert.isNull = function(value, opt_message) {};
+/**
+ * @param {*} value
+ * @param {string=} opt_message
+ */
+assert.exists = function(value, opt_message) {};
+
+/**
+ * @param {*} value
+ * @param {string=} opt_message
+ */
+assert.notExists = function(value, opt_message) {};
+
/**
* @param {*} object
* @param {function(new: Object)} constructor
