refactor: sql-tools (#19717)

server/src/sql-tools/comparers/function.comparer.ts

@@ -0,0 +1,32 @@
+import { Comparer, DatabaseFunction, Reason } from 'src/sql-tools/types';
+
+export const compareFunctions: Comparer<DatabaseFunction> = {
+  onMissing: (source) => [
+    {
+      type: 'FunctionCreate',
+      function: source,
+      reason: Reason.MissingInTarget,
+    },
+  ],
+  onExtra: (target) => [
+    {
+      type: 'FunctionDrop',
+      functionName: target.name,
+      reason: Reason.MissingInSource,
+    },
+  ],
+  onCompare: (source, target) => {
+    if (source.expression !== target.expression) {
+      const reason = `function expression has changed (${source.expression} vs ${target.expression})`;
+      return [
+        {
+          type: 'FunctionCreate',
+          function: source,
+          reason,
+        },
+      ];
+    }
+
+    return [];
+  },
+};