From e4db00903bbd2e2c59f5a86274ea70d5d031d668 Mon Sep 17 00:00:00 2001
From: Kyle Cunningham <codeincarnate@users.noreply.github.com>
Date: Wed, 15 May 2024 14:29:30 -0500
Subject: [PATCH] Format String Transformation: Add applicability function
 (#87777)

* Add applicability function

* Prettier
---
 .../transformations/transformers/formatString.ts  | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/packages/grafana-data/src/transformations/transformers/formatString.ts b/packages/grafana-data/src/transformations/transformers/formatString.ts
index fb72dd4df0e..2e46e4d5a72 100644
--- a/packages/grafana-data/src/transformations/transformers/formatString.ts
+++ b/packages/grafana-data/src/transformations/transformers/formatString.ts
@@ -1,7 +1,7 @@
 import { map } from 'rxjs/operators';
 
 import { DataFrame, Field, FieldType } from '../../types';
-import { DataTransformerInfo, FieldMatcher } from '../../types/transformations';
+import { DataTransformerInfo, FieldMatcher, TransformationApplicabilityLevels } from '../../types/transformations';
 import { fieldMatchers } from '../matchers';
 import { FieldMatcherID } from '../matchers/ids';
 
@@ -69,6 +69,19 @@ export const formatStringTransformer: DataTransformerInfo<FormatStringTransforme
   name: 'Format string',
   description: 'Manipulate string fields formatting',
   defaultOptions: { stringField: '', outputFormat: FormatStringOutput.UpperCase },
+  isApplicable: (data: DataFrame[]) => {
+    // Search for a string field
+    // if there is one then we can use this transformation
+    for (const frame of data) {
+      for (const field of frame.fields) {
+        if (field.type === 'string') {
+          return TransformationApplicabilityLevels.Applicable;
+        }
+      }
+    }
+
+    return TransformationApplicabilityLevels.NotApplicable;
+  },
   operator: (options) => (source) =>
     source.pipe(
       map((data) => {