react app

react-app/node_modules/react/lib/keyMirror.js

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+/**
+ * Copyright 2013-2015, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @providesModule keyMirror
+ * @typechecks static-only
+ */
+
+'use strict';
+
+var invariant = require("./invariant");
+
+/**
+ * Constructs an enumeration with keys equal to their value.
+ *
+ * For example:
+ *
+ *   var COLORS = keyMirror({blue: null, red: null});
+ *   var myColor = COLORS.blue;
+ *   var isColorValid = !!COLORS[myColor];
+ *
+ * The last line could not be performed if the values of the generated enum were
+ * not equal to their keys.
+ *
+ *   Input:  {key1: val1, key2: val2}
+ *   Output: {key1: key1, key2: key2}
+ *
+ * @param {object} obj
+ * @return {object}
+ */
+var keyMirror = function(obj) {
+  var ret = {};
+  var key;
+  ("production" !== process.env.NODE_ENV ? invariant(
+    obj instanceof Object && !Array.isArray(obj),
+    'keyMirror(...): Argument must be an object.'
+  ) : invariant(obj instanceof Object && !Array.isArray(obj)));
+  for (key in obj) {
+    if (!obj.hasOwnProperty(key)) {
+      continue;
+    }
+    ret[key] = key;
+  }
+  return ret;
+};
+
+module.exports = keyMirror;