Bump to v4.0.0.

isNative.js

@@ -0,0 +1,53 @@
+import isFunction from './isFunction';
+import isHostObject from './internal/isHostObject';
+import isObjectLike from './isObjectLike';
+
+/** Used to match `RegExp` [syntax characters](http://ecma-international.org/ecma-262/6.0/#sec-patterns). */
+var reRegExpChar = /[\\^$.*+?()[\]{}|]/g;
+
+/** Used to detect host constructors (Safari > 5). */
+var reIsHostCtor = /^\[object .+?Constructor\]$/;
+
+/** Used for built-in method references. */
+var objectProto = Object.prototype;
+
+/** Used to resolve the decompiled source of functions. */
+var funcToString = Function.prototype.toString;
+
+/** Used to check objects for own properties. */
+var hasOwnProperty = objectProto.hasOwnProperty;
+
+/** Used to detect if a method is native. */
+var reIsNative = RegExp('^' +
+  funcToString.call(hasOwnProperty).replace(reRegExpChar, '\\$&')
+  .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
+);
+
+/**
+ * Checks if `value` is a native function.
+ *
+ * @static
+ * @memberOf _
+ * @category Lang
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is a native function, else `false`.
+ * @example
+ *
+ * _.isNative(Array.prototype.push);
+ * // => true
+ *
+ * _.isNative(_);
+ * // => false
+ */
+function isNative(value) {
+  if (value == null) {
+    return false;
+  }
+  if (isFunction(value)) {
+    return reIsNative.test(funcToString.call(value));
+  }
+  return isObjectLike(value) &&
+    (isHostObject(value) ? reIsNative : reIsHostCtor).test(value);
+}
+
+export default isNative;