feat: add ability to check for existence of a field

.changeset/nine-bears-speak.md

@@ -0,0 +1,6 @@
+---
+"@openstapps/backend": minor
+"@openstapps/core": minor
+---
+
+Add the ability to filter by existence of a field

backend/backend/src/storage/elasticsearch/query/filters/value.ts

@@ -21,16 +21,31 @@ import {QueryDslSpecificQueryContainer} from '../../types/util.js';
  */
 export function buildValueFilter(
   filter: SCSearchValueFilter,
-): QueryDslSpecificQueryContainer<'term'> | QueryDslSpecificQueryContainer<'terms'> {
-  return Array.isArray(filter.arguments.value)
-    ? {
-        terms: {
-          [`${filter.arguments.field}.raw`]: filter.arguments.value,
+):
+  | QueryDslSpecificQueryContainer<'exists'>
+  | QueryDslSpecificQueryContainer<'term'>
+  | QueryDslSpecificQueryContainer<'terms'> {
+  switch (typeof filter.arguments.value) {
+    case 'undefined': {
+      return {
+        exists: {
+          field: filter.arguments.field,
         },
-      }
-    : {
+      };
+    }
+    case 'string': {
+      return {
         term: {
           [`${filter.arguments.field}.raw`]: filter.arguments.value,
         },
       };
+    }
+    case 'object': {
+      return {
+        terms: {
+          [`${filter.arguments.field}.raw`]: filter.arguments.value,
+        },
+      };
+    }
+  }
 }

packages/core/src/protocol/search/filters/value.ts

@@ -33,6 +33,8 @@ export interface SCValueFilterArguments extends SCSearchAbstractFilterArguments
 
   /**
    * Value to filter. One or more values has to match the field exactly.
+   *
+   * Leaving the value out will check if the field exists.
    */
-  value: string | string[];
+  value?: string | string[];
 }