From d16e8a00afc43f7365acc9e3f9d62d627bba3153 Mon Sep 17 00:00:00 2001
From: David Enke <david@enke.dev>
Date: Tue, 12 Nov 2024 16:14:49 +0100
Subject: [PATCH] chore: externalize transform utils

---
 src/transformers/field.transform.ts | 32 +++++++------------
 src/utils/transform.utils.ts        | 48 +++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 21 deletions(-)

diff --git a/src/transformers/field.transform.ts b/src/transformers/field.transform.ts
index 523120c..23e2536 100644
--- a/src/transformers/field.transform.ts
+++ b/src/transformers/field.transform.ts
@@ -2,7 +2,13 @@ import type * as Decap from 'decap-cms-core';
 import type * as Zod from 'zod';
 
 import type { DecapWidgetType } from '../utils/decap.utils.js';
-import type { Transformer, TransformResult } from '../utils/transform.utils.js';
+import {
+  applyDefaultValue,
+  applyDescription,
+  applyOptional,
+  type Transformer,
+  type TransformResult,
+} from '../utils/transform.utils.js';
 import { transformBooleanField } from './field-boolean.transform.js';
 import { transformCodeField } from './field-code.transform.js';
 import { transformDateTimeField } from './field-date-time.transform.js';
@@ -88,26 +94,10 @@ export const transformField: Transformer = (field, z) => {
       break;
   }
 
-  // flag field as optional - it should be explicitly `optional()` or `nullable()`,
-  // but for me it's not quite clear right now what is specified on the Decap side
-  // fyi: https://gist.github.com/ciiqr/ee19e9ff3bb603f8c42b00f5ad8c551e
-  if (field.required === false) {
-    runtime = runtime.nullish();
-    cptime = `${cptime}.nullish()`;
-  }
-
-  // set a default value
-  const { default: def } = field as { default?: any };
-  // cannot set null as default value on mandatory fields
-  if (def !== undefined || (def === null && !field.required)) {
-    runtime = runtime.default(def);
-    cptime = `${cptime}.default(${JSON.stringify(def)})`;
-  }
-
-  // add a description
-  const description = field.hint ?? field.label ?? field.name;
-  runtime = runtime.describe(description);
-  cptime = `${cptime}.describe('${description}')`;
+  // flag field as optional, set a default value and add a description if available
+  ({ cptime, runtime } = applyOptional(field, { cptime, runtime }));
+  ({ cptime, runtime } = applyDefaultValue(field, { cptime, runtime }));
+  ({ cptime, runtime } = applyDescription(field, { cptime, runtime }));
 
   return { runtime, cptime };
 };
diff --git a/src/utils/transform.utils.ts b/src/utils/transform.utils.ts
index c61119a..c22c4f7 100644
--- a/src/utils/transform.utils.ts
+++ b/src/utils/transform.utils.ts
@@ -28,6 +28,54 @@ export type TransformResult<R = Zod.ZodType> = {
   cptime: string;
 };
 
+/**
+ * Flags a field as optional if it is not required.
+ */
+export function applyOptional(field: Decap.CmsField, result: TransformResult): TransformResult {
+  // it should be explicitly `optional()` or `nullable()`,
+  // but for me it's not quite clear right now what is specified on the Decap side
+  // fyi: https://gist.github.com/ciiqr/ee19e9ff3bb603f8c42b00f5ad8c551e
+  if (field.required === false) {
+    return {
+      runtime: result.runtime.nullish(),
+      cptime: `${result.cptime}.nullish()`,
+    };
+  }
+  return result;
+}
+
+/**
+ * Sets a default value if reasonable.
+ */
+export function applyDefaultValue(field: Decap.CmsField, result: TransformResult): TransformResult {
+  const { default: def } = field as { default?: any };
+  // cannot set null as default value on mandatory fields
+  if (def === undefined || (def === null && field.required)) {
+    return result;
+  }
+
+  // set default value
+  return {
+    runtime: result.runtime.default(def),
+    cptime: `${result.cptime}.default(${JSON.stringify(def)})`,
+  };
+}
+
+/**
+ * Derives and sets a description if available.
+ */
+export function applyDescription(field: Decap.CmsField, result: TransformResult): TransformResult {
+  // derive potential description
+  const description = field.hint ?? field.label ?? field.name;
+  if (description === undefined) return result;
+
+  // set a description
+  return {
+    runtime: result.runtime.describe(description),
+    cptime: `${result.cptime}.describe('${description}')`,
+  };
+}
+
 /**
  * Transforms a Decap CMS collection config into an Astro collection schema.
  */