graphql-expert

Files (1)

• SKILL.md

SKILL.md (first lines)

# GraphQL Expert

Comprehensive guide for designing and implementing GraphQL APIs.

## GraphQL Fundamentals

### What is GraphQL?

```
GraphQL is a query language for APIs that:
✓ Lets clients request exactly what they need
✓ Gets multiple resources in one request
✓ Uses a type system to describe data
✓ Provides introspection (self-documenting)

GraphQL vs REST:
┌─────────────────────────────────────────┐
│ REST: Multiple endpoints, fixed shapes  │
│ GET /users/1                            │
│ GET /users/1/posts                      │
│ GET /users/1/followers                  │
├─────────────────────────────────────────┤
│ GraphQL: Single endpoint, flexible      │
│ POST /graphql                           │
│ query { user(id: 1) {                   │
│   name                                  │
│   posts { title }                       │
│   followers { name }                    │
│ }}                                      │
└─────────────────────────────────────────┘
```

---

## Schema Design

### Type System

```graphql
# Scalar Types (built-in)
String, Int, Float, Boolean, ID

# Custom Scalar
scalar DateTime
scalar JSON

# Object Type
type User {
  id: ID!
  email: String!
  name: String
  createdAt: DateTime!
  posts: [Post!]!
}

# Enum
enum Role {
  ADMIN
  USER
  GUEST
}

# Interface
interface Node {
  id: ID!
}

type User implements Node {
  id: ID!
  # ... other fields
}

# Union
union SearchResult = User | Post | Comment

# Input Type (for mutations)
input CreateUserInput {
  email: String!
  name: String!
  role: Role = USER
}
```

### Nullability

```graphql
# Field modifiers:
String      # Nullable string
String!     # Non-null string
[String]    # Nullable list of nullable strings
[String!]   # Nullable list of non-null strings
[String]!   # Non-null list of nullable strings
[String!]!  # Non-null list of non-null strings

# Best practice:
# - Make fields nullable by default
# - Use ! only when guaranteed non-null
# - Lists should usually be non-null: [Item!]!
```

### Schema Structure

```graphql
# Root Types
type Query {
  # Read operations
  user(id: ID!): User
  users(limit: Int, offset: Int): [User!]!
  me: User
}

type Mutation {
  # Write operations
  createUser(input: CreateUserInput!): User!
  updateUser(id: ID!, input: UpdateUserInput!): User!
  deleteUser(id: ID!): Boolean!
}

type Subscription {

From travisjneuman/.claude, MIT.

More from travisjneuman/.claude