Bump to v4.0.0.

internal/assocIndexOf.js

@@ -0,0 +1,23 @@
+define(['../eq'], function(eq) {
+
+  /**
+   * Gets the index at which the first occurrence of `key` is found in `array`
+   * of key-value pairs.
+   *
+   * @private
+   * @param {Array} array The array to search.
+   * @param {*} key The key to search for.
+   * @returns {number} Returns the index of the matched value, else `-1`.
+   */
+  function assocIndexOf(array, key) {
+    var length = array.length;
+    while (length--) {
+      if (eq(array[length][0], key)) {
+        return length;
+      }
+    }
+    return -1;
+  }
+
+  return assocIndexOf;
+});