fortify-schema/src/core/private/test-when-field-inference.ts

TypeScript interface-like schema validation system that's easier to use than Zod

import { Interface } from "../schema/mode/interfaces/Interface";
import { When } from "../schema/extensions/components/ConditionalValidation";

console.log("🔧 WHEN.FIELD() TYPESCRIPT INFERENCE TEST");
console.log("=========================================\n");

// Test When.field() with TypeScript inference
const WhenFieldSchema = Interface({
  role: "admin|user|guest",
  accountType: "free|premium|enterprise",
  
  // 📦 Import-based When.field() syntax - Should now have TypeScript inference!
  permissions: When.field("role").is("admin").then("boolean").else("string[]"),
  maxProjects: When.field("accountType").is("free").then("number").else("number"),
  paymentMethod: When.field("accountType").isNot("free").then("string").else("string?"),
  
  id: "positive",
  name: "string"
});

console.log("✅ When.field() schema created successfully!");

// Test case 1: Admin user
const adminData = {
  role: "admin" as const,
  accountType: "premium" as const,
  permissions: true,        // Should be inferred as boolean | string[] (union type)
  maxProjects: 50,          // Should be inferred as number
  paymentMethod: "credit",  // Should be inferred as string | (string | undefined)
  id: 1,
  name: "Admin User"
};

// Test case 2: Regular user  
const userData = {
  role: "user" as const,
  accountType: "free" as const,
  permissions: ["read"],    // Should be inferred as boolean | string[] (union type)
  maxProjects: 3,           // Should be inferred as number
  id: 2,
  name: "Regular User"
};

// Test validation
const adminResult = WhenFieldSchema.safeParse(adminData);
const userResult = WhenFieldSchema.safeParse(userData);

console.log("✅ Admin validation:", adminResult.success);
console.log("✅ User validation:", userResult.success);

// Test type errors - these should show TypeScript errors
console.log("\n🎯 Testing TypeScript Error Detection:");

// This should show a TypeScript error if inference is working
const invalidData = {
  role: "admin" as const,
  accountType: "premium" as const,
  permissions: 123,         // ❌ Should show error: number not assignable to boolean | string[]
  maxProjects: 50,
  paymentMethod: "credit",
  id: 1,
  name: "Admin User"
};

console.log("🔧 WHEN.FIELD() INFERENCE SUMMARY");
console.log("=================================");
console.log("✅ When.field() syntax: Should show union types (boolean | string[])");
console.log("✅ TypeScript errors: Should catch type mismatches");
console.log("✅ Runtime validation: Should work correctly");

console.log("\n🚀 When.field() TypeScript inference test complete!");
console.log("   Check the IDE to see if permissions shows proper types!");