Project 2 — Dynamic Form Builder (Schema-Driven Forms)

🧭 Introduction

Forms are everywhere:

• Surveys
• Admin panels
• Onboarding flows
• Configuration screens

But in real-world applications, forms are rarely hardcoded.

Instead, they are:

• Generated dynamically
• Driven by backend schemas
• Reusable across multiple screens

This project teaches you how to build a Dynamic Form Builder — a skill that immediately levels you up as a React developer.

⚠️ This project mirrors how enterprise SaaS products handle forms.

🎯 Project Goals

By completing this project, you will learn how to:

• Build forms dynamically using schemas
• Separate form structure from UI
• Handle validation at scale
• Reuse form components efficiently
• Manage form state cleanly
• Design extensible form architectures

🧠 What We Are Building

✅ Dynamic Form Builder App

Features:

• Form generated from JSON schema
• Multiple input types
• Field-level validation
• Conditional fields
• Dynamic submit handling
• Error handling & feedback
• Fully reusable form engine

🧩 What Is a Schema-Driven Form?

Instead of writing JSX like this ❌:

<input />
<select />
<textarea />

We define a schema ✅:

const formSchema = [
  {
    name: "email",
    label: "Email",
    type: "text",
    required: true
  },
  {
    name: "role",
    label: "Role",
    type: "select",
    options: ["Admin", "User"]
  }
];

The UI is generated automatically.

🏗️ High-Level Architecture

src/
│
├── form-builder/
│   ├── FormRenderer.tsx
│   ├── FieldRenderer.tsx
│   ├── fields/
│   │   ├── TextField.tsx
│   │   ├── SelectField.tsx
│   │   └── CheckboxField.tsx
│   ├── validators/
│   └── types.ts
│
├── hooks/
│   └── useFormState.ts
│
├── schemas/
│   └── userFormSchema.ts

This design is:
✔ Modular
✔ Extensible
✔ Testable

🧠 Core Concepts Used

🧩 Schema Definition (Typed)

export type FieldSchema =
  | {
      type: "text";
      name: string;
      label: string;
      required?: boolean;
    }
  | {
      type: "select";
      name: string;
      label: string;
      options: string[];
    };

This prevents invalid schemas at compile time.

🧠 Form Renderer (Engine)

function FormRenderer({ schema, onSubmit }) {
  const { values, handleChange, errors } = useFormState(schema);

  return (
    <form onSubmit={onSubmit}>
      {schema.map(field => (
        <FieldRenderer
          key={field.name}
          field={field}
          value={values[field.name]}
          error={errors[field.name]}
          onChange={handleChange}
        />
      ))}
      <button type="submit">Submit</button>
    </form>
  );
}

The form engine:
✔ Knows nothing about UI
✔ Works for any schema

🧠 Field Renderer (Factory Pattern)

function FieldRenderer({ field, ...props }) {
  switch (field.type) {
    case "text":
      return <TextField {...props} />;
    case "select":
      return <SelectField {...props} />;
    default:
      return null;
  }
}

Adding new field types is easy.

🧪 Validation Strategy

Validation is:

• Schema-driven
• Centralized
• Reusable

if (field.required && !value) {
  errors[field.name] = "Required";
}

No scattered validation logic.

🔄 Conditional Fields (Advanced Feature)

{
  name: "company",
  label: "Company",
  type: "text",
  showIf: { field: "role", equals: "Admin" }
}

Rendered only when conditions match.

🧠 useFormState Hook

function useFormState(schema) {
  const [values, setValues] = useState({});
  const [errors, setErrors] = useState({});

  const handleChange = (name, value) => {
    setValues(v => ({ ...v, [name]: value }));
  };

  return { values, errors, handleChange };
}

Encapsulates all form logic.

🧪 Testing Strategy

Tests cover:

• Field rendering
• Conditional logic
• Validation errors
• Submission payload

Example:

expect(screen.getByText("Email is required"))
  .toBeInTheDocument();

⚡ Performance Considerations

• Memoized field components
• Controlled re-renders
• Minimal state updates

Important for large forms.

🎯 Real-World Use Cases

This architecture is used in:

• Survey tools
• Admin dashboards
• CMS platforms
• SaaS onboarding flows

❓ FAQs — Project 2

🔹 Is this better than React Hook Form?

This teaches how form libraries work internally.

🔹 Can I integrate React Hook Form later?

Yes — this architecture adapts easily.

🔹 Is this interview-worthy?

Absolutely — very impressive.

🔹 Can I extend this project?

Yes — add date pickers, file uploads, async validation.

🧠 Quick Recap

✔ Schema-driven forms
✔ Dynamic UI generation
✔ Centralized validation
✔ Reusable architecture
✔ Production-ready design

🎉 Conclusion

This project moves you from:

“I can build forms”

to:

“I can build form systems.”

That’s a huge leap in frontend engineering maturity.

👉 Next Project

Project 3 — SaaS-Style Frontend (Auth, Billing & Protected Flows)