Bump to v4.0.0.

internal/addMapEntry.js

@@ -0,0 +1,17 @@
+define([], function() {
+
+  /**
+   * Adds the key-value `pair` to `map`.
+   *
+   * @private
+   * @param {Object} map The map to modify.
+   * @param {Array} pair The key-value pair to add.
+   * @returns {Object} Returns `map`.
+   */
+  function addMapEntry(map, pair) {
+    map.set(pair[0], pair[1]);
+    return map;
+  }
+
+  return addMapEntry;
+});