Bump to v4.0.0.

subtract.js

@@ -0,0 +1,32 @@
+define([], function() {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
+  /**
+   * Subtract two numbers.
+   *
+   * @static
+   * @memberOf _
+   * @category Math
+   * @param {number} minuend The first number in a subtraction.
+   * @param {number} subtrahend The second number in a subtraction.
+   * @returns {number} Returns the difference.
+   * @example
+   *
+   * _.subtract(6, 4);
+   * // => 2
+   */
+  function subtract(minuend, subtrahend) {
+    var result;
+    if (minuend !== undefined) {
+      result = minuend;
+    }
+    if (subtrahend !== undefined) {
+      result = result === undefined ? subtrahend : (result - subtrahend);
+    }
+    return result;
+  }
+
+  return subtract;
+});