1 files changed, 68 insertions, 0 deletions
diff --git a/node_modules/fbjs/lib/shallowEqual.js.flow b/node_modules/fbjs/lib/shallowEqual.js.flow
new file mode 100644
index 000000000..8b4e3172a
--- /dev/null
+++ b/node_modules/fbjs/lib/shallowEqual.js.flow
@@ -0,0 +1,68 @@
+/**
+ * Copyright (c) 2013-present, 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 shallowEqual
+ * @typechecks
+ * @flow
+ */
+
+/*eslint-disable no-self-compare */
+
+'use strict';
+
+const hasOwnProperty = Object.prototype.hasOwnProperty;
+
+/**
+ * inlined Object.is polyfill to avoid requiring consumers ship their own
+ * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is
+ */
+function is(x: mixed, y: mixed): boolean {
+  // SameValue algorithm
+  if (x === y) {
+    // Steps 1-5, 7-10
+    // Steps 6.b-6.e: +0 != -0
+    // Added the nonzero y check to make Flow happy, but it is redundant
+    return x !== 0 || y !== 0 || 1 / x === 1 / y;
+  } else {
+    // Step 6.a: NaN == NaN
+    return x !== x && y !== y;
+  }
+}
+
+/**
+ * Performs equality by iterating through keys on an object and returning false
+ * when any key has values which are not strictly equal between the arguments.
+ * Returns true when the values of all keys are strictly equal.
+ */
+function shallowEqual(objA: mixed, objB: mixed): boolean {
+  if (is(objA, objB)) {
+    return true;
+  }
+
+  if (typeof objA !== 'object' || objA === null || typeof objB !== 'object' || objB === null) {
+    return false;
+  }
+
+  const keysA = Object.keys(objA);
+  const keysB = Object.keys(objB);
+
+  if (keysA.length !== keysB.length) {
+    return false;
+  }
+
+  // Test for A's keys different from B.
+  for (let i = 0; i < keysA.length; i++) {
+    if (!hasOwnProperty.call(objB, keysA[i]) || !is(objA[keysA[i]], objB[keysA[i]])) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+module.exports = shallowEqual;
+\ No newline at end of file