Move a few more files into events src (#36574)

src/events/lib/middleware-errors.js

@@ -0,0 +1,38 @@
+import { pick, snakeCase } from 'lodash-es'
+import { randomUUID } from 'crypto'
+
+// https://ajv.js.org/api.html#error-objects
+const errorKeys = [
+  'keyword',
+  'instancePath',
+  'schemaPath',
+  'params',
+  'propertyName',
+  'message',
+  'schema',
+  'parentSchema',
+  'data',
+]
+
+export function formatErrors(errors, body) {
+  return errors.map((error) => ({
+    event_id: randomUUID(),
+    version: '1.0.0',
+    created: new Date().toISOString(),
+    raw: makeString(body),
+
+    // We convert to snake_case because dealing with case in SQL is unfortunate.
+    // Ensure the result is a string or undefined
+    ...Object.fromEntries(
+      Object.entries(pick(error, errorKeys)).map(([key, value]) => [
+        snakeCase(key),
+        makeString(value),
+      ])
+    ),
+  }))
+}
+
+// Leave strings alone, otherwise convert to either string or undefined
+function makeString(value) {
+  return typeof value === 'string' ? value : JSON.stringify(value)
+}