--- /dev/null
+var getMapData = require('./_getMapData');
+
+/**
+ * Sets the map `key` to `value`.
+ *
+ * @private
+ * @name set
+ * @memberOf MapCache
+ * @param {string} key The key of the value to set.
+ * @param {*} value The value to set.
+ * @returns {Object} Returns the map cache instance.
+ */
+function mapCacheSet(key, value) {
+ var data = getMapData(this, key),
+ size = data.size;
+
+ data.set(key, value);
+ this.size += data.size == size ? 0 : 1;
+ return this;
+}
+
+module.exports = mapCacheSet;