Bump to v4.0.0.

internal/createRound.js

@@ -1,13 +1,7 @@
-define([], function() {
-
-  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
-  var undefined;
-
-  /** Native method references. */
-  var pow = Math.pow;
+define(['../toInteger', '../toNumber', '../toString'], function(toInteger, toNumber, toString) {
 
   /**
-   * Creates a `_.ceil`, `_.floor`, or `_.round` function.
+   * Creates a function like `_.round`.
    *
    * @private
    * @param {string} methodName The name of the `Math` method to use when rounding.
@@ -16,10 +10,16 @@ define([], function() {
   function createRound(methodName) {
     var func = Math[methodName];
     return function(number, precision) {
-      precision = precision === undefined ? 0 : (+precision || 0);
+      number = toNumber(number);
+      precision = toInteger(precision);
       if (precision) {
-        precision = pow(10, precision);
-        return func(number * precision) / precision;
+        // Shift with exponential notation to avoid floating-point issues.
+        // See [MDN](https://mdn.io/round#Examples) for more details.
+        var pair = (toString(number) + 'e').split('e'),
+            value = func(pair[0] + 'e' + (+pair[1] + precision));
+
+        pair = (toString(value) + 'e').split('e');
+        return +(pair[0] + 'e' + (+pair[1] - precision));
       }
       return func(number);
     };