Add Generate Inferred Type From Zod Schema as a typescript TIL

Author: jbranchaud

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1232 TILs and counting..._
+_1233 TILs and counting..._
 
 ---
 
@@ -1136,6 +1136,7 @@ _1232 TILs and counting..._
 - [Compiler Checks For Unused Params And Variables](typescript/compiler-checks-for-unused-params-and-variables.md)
 - [Extract Object Type Keys Into A Union Type](typescript/extract-object-type-keys-into-a-union-type.md)
 - [Extract Object Type Values Into A Union Type](typescript/extract-object-type-values-into-a-union-type.md)
+- [Generate Inferred Type From Zod Schema](typescript/generate-inferred-type-from-zod-schema.md)
 - [Interfaces With The Same Name Are Merged](typescript/interfaces-with-the-same-name-are-merged.md)
 - [Re-Export An Imported Type](typescript/re-export-an-imported-type.md)
 - [Type Narrowing With Similarly Shaped Objects](typescript/type-narrowing-with-similarly-shaped-objects.md)

typescript/generate-inferred-type-from-zod-schema.md

@@ -0,0 +1,56 @@
+# Generate Inferred Type From Zod Schema
+
+One of the killer features of [`Zod`](https://github.com/colinhacks/zod) is
+that it does double-duty. When you define a schema, you can use that for
+runtime checks. You can also generate an inferred type from that schema for
+static type checking.
+
+Let's say I have the following schema defined for data representing a
+_contact_.
+
+```typescript
+import {z} from 'zod'
+
+const contactSchema = z.object({
+  person: z.object({
+    firstName: z.string(),
+    lastName: z.string()
+  }),
+  email: z.string().email(),
+})
+```
+
+I can use this schema along with Zod's
+[`z.infer()`](https://github.com/colinhacks/zod#type-inference) function to
+generate a type that I can use throughout my codebase.
+
+```typescript
+const createContact = (data: z.infer<typeof contactSchema>) => {
+  // ...
+}
+```
+
+If I inspect data, I can see that I get an object type generated from the
+`contactSchema`.
+
+```typescript
+/* data: {
+ *    person: {
+ *        firstName: string;
+ *        lastName: string;
+ *    };
+ *    email: string;
+ * }
+ */
+```
+
+That works, but looks a bit cluttered. I could pull it out into a defined type.
+One that could even be exported if I was so inclined.
+
+```typescript
+export type Contact = z.infer<typeof contactSchema>
+
+const createContact = (data: Contact) => {
+  // ...
+}
+```