Add Get Readable Errors From Schema Parse as a Zod TIL

zod/get-readable-errors-from-schema-parse.md

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+# Get Readable Errors From Schema Parse
+
+Let's say we have the following schema for validating the data used to create a
+new post record:
+
+```typescript
+const NewPostSchema = z.object({
+  title: z.string().min(1, "Title is required"),
+  slug: z.string().min(1, "Slug is required"),
+  markdown: z.string().min(1, "Markdown is required"),
+});
+```
+
+When we (safe) parse some incoming user input with that schema and, for
+example, one of the fields is empty, then the validation will fail and we'll
+get some errors.
+
+```typescript
+const result = NewPostSchema.safeParse(userInput)
+
+if(!result.success) {
+  result.error;
+  // ZodError: [
+  //   {
+  //     "code": "too_small",
+  //     "minimum": 1,
+  //     "type": "string",
+  //     "inclusive": true,
+  //     "exact": false,
+  //     "message": "Slug is required",
+  //     "path": [
+  //       "slug"
+  //     ]
+  //   }
+  // ]
+}
+```
+
+That packs a lot of information. But if we are just trying to get something
+minimal and actionable we can show to a user, we might want to flatten the
+errors:
+
+```typescript
+const result = NewPostSchema.safeParse(userInput)
+
+if(!result.success) {
+  result.error.flatten().fieldErrors;
+  // { slug: [ 'Slug is required' ] }
+}
+```
+
+[source](https://github.com/colinhacks/zod/blob/master/ERROR_HANDLING.md#flattening-errors)