feat: generateExample util function

Author: omermecitoglu

src/utils/generateExample.ts

@@ -0,0 +1,103 @@
+import { ZodBigInt, ZodBoolean, ZodEnum, ZodNull, ZodNullable, ZodNumber, ZodObject, ZodOptional, ZodString, type ZodType, type ZodTypeDef, ZodUndefined } from "zod";
+
+export default function generateExample<I, O>(
+  schema: ZodType<O, ZodTypeDef, I>,
+  ignoreOptionals: boolean,
+  keyName?: string,
+  nullable: boolean = false,
+): O {
+  if ("defaultValue" in schema._def && typeof schema._def.defaultValue === "function") {
+    return schema._def.defaultValue() as unknown as O;
+  }
+  if (schema instanceof ZodOptional) {
+    const innerSchema = schema._def.innerType;
+    if (ignoreOptionals) {
+      return undefined as unknown as O;
+    }
+    return generateExample(innerSchema, ignoreOptionals, keyName);
+  }
+  if (schema instanceof ZodNullable) {
+    const innerSchema = schema._def.innerType;
+    return (generateExample(innerSchema, ignoreOptionals, keyName, true) ?? null) as unknown as O;
+  }
+  if (schema instanceof ZodObject) {
+    const entries = Object.entries(schema.shape).map(([key, childSchema]) => {
+      return [key, generateExample(childSchema as ZodType, ignoreOptionals, key)] as const;
+    }).filter(([_, value]) => typeof value !== "undefined");
+    return Object.fromEntries(entries) as unknown as O;
+  }
+  if (schema instanceof ZodEnum) {
+    const values = schema._def.values;
+    if (values.length) {
+      return values[0] as unknown as O;
+    }
+  }
+  if (schema instanceof ZodNumber) {
+    if (schema.minValue) {
+      return schema.minValue as unknown as O;
+    }
+    if (schema._def.checks.length) {
+      for (const check of schema._def.checks) {
+        if (check.kind === "max" && check.value < 1) {
+          return -1 as unknown as O;
+        }
+        if (check.kind === "multipleOf") {
+          return check.value as unknown as O;
+        }
+      }
+    }
+    return 1 as unknown as O;
+  }
+  if (schema instanceof ZodBigInt) {
+    return 1n as unknown as O;
+  }
+  if (schema instanceof ZodBoolean) {
+    return false as unknown as O;
+  }
+  if (schema instanceof ZodUndefined) {
+    return undefined as unknown as O;
+  }
+  if (schema instanceof ZodNull) {
+    return null as unknown as O;
+  }
+  if (schema instanceof ZodString) {
+    if (schema.isEmail) {
+      return "[email protected]" as unknown as O;
+    }
+    if (schema.isURL) {
+      return "https://example.com" as unknown as O;
+    }
+    if (schema.isEmoji) {
+      return "😀" as unknown as O;
+    }
+    if (schema.isUUID) {
+      return "aa35d4a1-8f23-4cee-847c-2bfe89dc87c1" as unknown as O;
+    }
+    if (schema.isIP) {
+      return "192.168.1.1" as unknown as O;
+    }
+    if (schema.isDatetime) {
+      return "2024-11-06T07:00:00.137Z" as unknown as O;
+    }
+    if (schema._def.checks.length) {
+      const example = ["example"];
+      for (const check of schema._def.checks) {
+        if (check.kind === "startsWith") {
+          example.unshift(check.value);
+        }
+        if (check.kind === "endsWith") {
+          example.push(check.value);
+        }
+      }
+      return example.join("") as unknown as O;
+    }
+    if (keyName) {
+      return `example ${keyName}` as unknown as O;
+    }
+    if (nullable) {
+      return "example nullable string" as unknown as O;
+    }
+    return "example string" as unknown as O;
+  }
+  throw new Error("Unknown zod schema");
+}