diff --git a/packages/grafana-data/src/transformations/transformers/merge.test.ts b/packages/grafana-data/src/transformations/transformers/merge.test.ts index a56c446dd78..8fb57860490 100644 --- a/packages/grafana-data/src/transformations/transformers/merge.test.ts +++ b/packages/grafana-data/src/transformations/transformers/merge.test.ts @@ -16,6 +16,20 @@ describe('Merge multiple to single', () => { mockTransformationsRegistry([mergeTransformer]); }); + it('skip combine one serie', async () => { + const seriesA = toDataFrame({ + name: 'A', + fields: [ + { name: 'Time', type: FieldType.time, values: [1000] }, + { name: 'Temp', type: FieldType.number, values: [1] }, + ], + }); + await expect(transformDataFrame([cfg], [seriesA])).toEmitValuesWith((received) => { + const result = received[0]; + expect(seriesA).toBe(result[0]); + }); + }); + it('combine two series into one', async () => { const seriesA = toDataFrame({ name: 'A', diff --git a/packages/grafana-data/src/transformations/transformers/merge.ts b/packages/grafana-data/src/transformations/transformers/merge.ts index ecc0e767e7c..cecbb1cf9c7 100644 --- a/packages/grafana-data/src/transformations/transformers/merge.ts +++ b/packages/grafana-data/src/transformations/transformers/merge.ts @@ -22,7 +22,7 @@ export const mergeTransformer: DataTransformerInfo = { operator: (options) => (source) => source.pipe( map((dataFrames) => { - if (!Array.isArray(dataFrames) || dataFrames.length === 0) { + if (!Array.isArray(dataFrames) || dataFrames.length <= 1) { return dataFrames; }