types: correct Median implementation

Author: vkarpov15

test/types/PipelineStage.test.ts

@@ -575,12 +575,3 @@ const vectorSearchStages: PipelineStage[] = [
     }
   }
 ];
-
-function median() {
-  const medianStage: PipelineStage = {
-    $median: {
-      input: ['$test01', '$test02', '$test03'],
-      method: 'approximate'
-    }
-  };
-}

test/types/expressions.test.ts

@@ -313,3 +313,7 @@ const filterLimit: Expression.Filter = {
     }
   ];
 })();
+
+function gh15209() {
+  const query: PipelineStage[] = [{ $group: { _id: null, median: { $median: { input: '$value', method: 'approximate' } } } }];
+}

types/expressions.d.ts

@@ -2301,6 +2301,18 @@ declare module 'mongoose' {
       }
     }
 
+    export interface Median {
+      /**
+       * Returns an approximation of the median, the 50th percentile, as a scalar value.
+       *
+       * @see https://www.mongodb.com/docs/v7.0/reference/operator/aggregation/median/
+       */
+      $median: {
+        input: number | Expression,
+        method: 'approximate'
+      }
+    }
+
     export interface StdDevPop {
       /**
        * Calculates the population standard deviation of the input values. Use if the values encompass the entire
@@ -2859,6 +2871,7 @@ declare module 'mongoose' {
     Expression.Locf |
     Expression.Max |
     Expression.MaxN |
+    Expression.Median |
     Expression.Min |
     Expression.MinN |
     Expression.Push |
@@ -2891,6 +2904,7 @@ declare module 'mongoose' {
     Expression.ExpMovingAvg |
     Expression.Integral |
     Expression.Max |
+    Expression.Median |
     Expression.Min |
     Expression.StdDevPop |
     Expression.StdDevSamp |

types/pipelinestage.d.ts

@@ -20,7 +20,6 @@ declare module 'mongoose' {
     | PipelineStage.ListSessions
     | PipelineStage.Lookup
     | PipelineStage.Match
-    | PipelineStage.Median
     | PipelineStage.Merge
     | PipelineStage.Out
     | PipelineStage.PlanCacheStats
@@ -188,14 +187,6 @@ declare module 'mongoose' {
       $match: FilterQuery<any>;
     }
 
-    export interface Median {
-      /** [`$median` reference](https://www.mongodb.com/docs/v7.0/reference/operator/aggregation/median/) */
-      $median: {
-        input: number | Expression,
-        method: 'approximate'
-      }
-    }
-
     export interface Merge {
       /** [`$merge` reference](https://www.mongodb.com/docs/manual/reference/operator/aggregation/merge/) */
       $merge: {