improve meta field flattening

src/plugins/data/common/search/tabify/tabify_docs.test.ts

@@ -63,6 +63,8 @@ describe('tabify_docs', () => {
  _source: {
  name: 'first',
  },
+ _routing: 'test',
+ _score: 1,
  fields: {
  date: ['1'],
  zzz: ['z'],

src/plugins/data/common/search/tabify/tabify_docs.ts

@@ -25,25 +25,12 @@ type ValidMetaFieldNames = keyof Pick<
  | '_source'
  | '_version'
 >;
-const VALID_META_FIELD_NAMES: ValidMetaFieldNames[] = [
- '_id',
- '_ignored',
- '_index',
- '_node',
- '_primary_term',
- '_routing',
- '_score',
- '_seq_no',
- '_shard',
- '_source',
- '_version',
-];
 
 function isValidMetaFieldName(field: string): field is ValidMetaFieldNames {
  // Since the array above is more narrowly typed than string[], we cannot use
  // string to find a value in here. We manually cast it to wider string[] type
  // so we're able to use `includes` on it.
- return (VALID_META_FIELD_NAMES as string[]).includes(field);
+ return field !== '_source' && field !== '_type' && field.at(0) === '_';
 }
 
 interface TabifyDocsOptions {
@@ -137,13 +124,14 @@ export function flattenHit(hit: Hit, indexPattern?: DataView, params?: TabifyDoc
  });
  }
 
- // Merge all valid meta fields into the flattened object
- // expect for _source (in case that was specified as a meta field)
+ // Merge all meta fields into the flattened object
  indexPattern?.metaFields?.forEach((metaFieldName) => {
- if (!isValidMetaFieldName(metaFieldName) || metaFieldName === '_source') {
+ if (!isValidMetaFieldName(metaFieldName)) {
  return;
  }
- flat[metaFieldName] = hit[metaFieldName];
+ if (hit[metaFieldName] !== undefined && !flat[metaFieldName]) {
+ flat[metaFieldName] = hit[metaFieldName];
+ }
  });
 
  // Use a proxy to make sure that keys are always returned in a specific order,