mongo works

parts/3/followAlong/node_modules/mongoose/lib/cast/int32.js

@@ -0,0 +1,36 @@
+'use strict';
+
+const isBsonType = require('../helpers/isBsonType');
+const assert = require('assert');
+
+/**
+ * Given a value, cast it to a Int32, or throw an `Error` if the value
+ * cannot be casted. `null` and `undefined` are considered valid.
+ *
+ * @param {Any} value
+ * @return {Number}
+ * @throws {Error} if `value` does not represent an integer, or is outside the bounds of an 32-bit integer.
+ * @api private
+ */
+
+module.exports = function castInt32(val) {
+  if (val == null) {
+    return val;
+  }
+  if (val === '') {
+    return null;
+  }
+
+  const coercedVal = isBsonType(val, 'Long') ? val.toNumber() : Number(val);
+
+  const INT32_MAX = 0x7FFFFFFF;
+  const INT32_MIN = -0x80000000;
+
+  if (coercedVal === (coercedVal | 0) &&
+      coercedVal >= INT32_MIN &&
+      coercedVal <= INT32_MAX
+  ) {
+    return coercedVal;
+  }
+  assert.ok(false);
+};