some progress

node_modules/mongoose/lib/error/divergentArray.js

@@ -0,0 +1,38 @@
+
+/*!
+ * Module dependencies.
+ */
+
+'use strict';
+
+const MongooseError = require('./');
+
+class DivergentArrayError extends MongooseError {
+  /**
+   * DivergentArrayError constructor.
+   * @param {Array<String>} paths
+   * @api private
+   */
+  constructor(paths) {
+    const msg = 'For your own good, using `document.save()` to update an array '
+            + 'which was selected using an $elemMatch projection OR '
+            + 'populated using skip, limit, query conditions, or exclusion of '
+            + 'the _id field when the operation results in a $pop or $set of '
+            + 'the entire array is not supported. The following '
+            + 'path(s) would have been modified unsafely:\n'
+            + '  ' + paths.join('\n  ') + '\n'
+            + 'Use Model.updateOne() to update these arrays instead.';
+    // TODO write up a docs page (FAQ) and link to it
+    super(msg);
+  }
+}
+
+Object.defineProperty(DivergentArrayError.prototype, 'name', {
+  value: 'DivergentArrayError'
+});
+
+/*!
+ * exports
+ */
+
+module.exports = DivergentArrayError;