Sync CSSCore from upstream

src/vendor/core/CSSCore.js

@@ -0,0 +1,114 @@
+/**
+ * Copyright 2013 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * @providesModule CSSCore
+ * @typechecks
+ */
+
+var invariant = require('invariant');
+
+/**
+ * The CSSCore module specifies the API (and implements most of the methods)
+ * that should be used when dealing with the display of elements (via their
+ * CSS classes and visibility on screeni. It is an API focused on mutating the
+ * display and not reading it as no logical state should be encoded in the
+ * display of elements.
+ */
+
+/**
+ * Tests whether the element has the class specified.
+ *
+ * Note: This function is not exported in CSSCore because CSS classNames should
+ * not store any logical information about the element. Use DataStore to store
+ * information on an element.
+ *
+ * @param {DOMElement} element the element to set the class on
+ * @param {string} className the CSS className
+ * @returns {boolean} true if the element has the class, false if not
+ */
+function hasClass(element, className) {
+  if (element.classList) {
+    return !!className && element.classList.contains(className);
+  }
+  return (' ' + element.className + ' ').indexOf(' ' + className + ' ') > -1;
+}
+
+var CSSCore = {
+
+  /**
+   * Adds the class passed in to the element if it doesn't already have it.
+   *
+   * @param {DOMElement} element the element to set the class on
+   * @param {string} className the CSS className
+   * @return {DOMElement} the element passed in
+   */
+  addClass: function(element, className) {
+    invariant(
+      !/\s/.test(className),
+      'CSSCore.addClass takes only a single class name. "%s" contains ' +
+      'multiple classes.', className
+    );
+
+    if (className) {
+      if (element.classList) {
+        element.classList.add(className);
+      } else if (!hasClass(element, className)) {
+        element.className = element.className + ' ' + className;
+      }
+    }
+    return element;
+  },
+
+  /**
+   * Removes the class passed in from the element
+   *
+   * @param {DOMElement} element the element to set the class on
+   * @param {string} className the CSS className
+   * @return {DOMElement} the element passed in
+   */
+  removeClass: function(element, className) {
+    invariant(
+      !/\s/.test(className),
+      'CSSCore.removeClass takes only a single class name. "%s" contains ' +
+      'multiple classes.', className
+    );
+
+    if (className) {
+      if (element.classList) {
+        element.classList.remove(className);
+      } else if (hasClass(element, className)) {
+        element.className = element.className
+          .replace(new RegExp('(^|\\s)' + className + '(?:\\s|$)', 'g'), '$1')
+          .replace(/\s+/g, ' ') // multiple spaces to one
+          .replace(/^\s*|\s*$/g, ''); // trim the ends
+      }
+    }
+    return element;
+  },
+
+  /**
+   * Helper to add or remove a class from an element based on a condition.
+   *
+   * @param {DOMElement} element the element to set the class on
+   * @param {string} className the CSS className
+   * @param {*} bool condition to whether to add or remove the class
+   * @return {DOMElement} the element passed in
+   */
+  conditionClass: function(element, className, bool) {
+    return (bool ? CSSCore.addClass : CSSCore.removeClass)(element, className);
+  }
+};
+
+module.exports = CSSCore;