Commit

node_modules/mongoose/lib/helpers/aggregate/prepareDiscriminatorPipeline.js

@@ -0,0 +1,39 @@
+'use strict';
+
+module.exports = function prepareDiscriminatorPipeline(pipeline, schema, prefix) {
+  const discriminatorMapping = schema && schema.discriminatorMapping;
+  prefix = prefix || '';
+
+  if (discriminatorMapping && !discriminatorMapping.isRoot) {
+    const originalPipeline = pipeline;
+    const filterKey = (prefix.length > 0 ? prefix + '.' : prefix) + discriminatorMapping.key;
+    const discriminatorValue = discriminatorMapping.value;
+
+    // If the first pipeline stage is a match and it doesn't specify a `__t`
+    // key, add the discriminator key to it. This allows for potential
+    // aggregation query optimizations not to be disturbed by this feature.
+    if (originalPipeline[0] != null &&
+        originalPipeline[0].$match &&
+        (originalPipeline[0].$match[filterKey] === undefined || originalPipeline[0].$match[filterKey] === discriminatorValue)) {
+      originalPipeline[0].$match[filterKey] = discriminatorValue;
+      // `originalPipeline` is a ref, so there's no need for
+      // aggregate._pipeline = originalPipeline
+    } else if (originalPipeline[0] != null && originalPipeline[0].$geoNear) {
+      originalPipeline[0].$geoNear.query =
+          originalPipeline[0].$geoNear.query || {};
+      originalPipeline[0].$geoNear.query[filterKey] = discriminatorValue;
+    } else if (originalPipeline[0] != null && originalPipeline[0].$search) {
+      if (originalPipeline[1] && originalPipeline[1].$match != null) {
+        originalPipeline[1].$match[filterKey] = originalPipeline[1].$match[filterKey] || discriminatorValue;
+      } else {
+        const match = {};
+        match[filterKey] = discriminatorValue;
+        originalPipeline.splice(1, 0, { $match: match });
+      }
+    } else {
+      const match = {};
+      match[filterKey] = discriminatorValue;
+      originalPipeline.unshift({ $match: match });
+    }
+  }
+};