GraphQL with Apollo Server

1// GraphQL with Apollo Server — Complete Example
2
3const { ApolloServer } = require("@apollo/server");
4const { startStandaloneServer } = require("@apollo/server/standalone");
5
6// 1. Type definitions (schema)
7const typeDefs = `#graphql
8  type User {
9    id: ID!
10    name: String!
11    email: String!
12    role: Role!
13    posts: [Post!]!
14    postCount: Int!
15    createdAt: String!
16  }
17
18  type Post {
19    id: ID!
20    title: String!
21    content: String
22    published: Boolean!
23    author: User!
24    tags: [String!]!
25    createdAt: String!
26  }
27
28  enum Role {
29    USER
30    ADMIN
31    MODERATOR
32  }
33
34  type Query {
35    users(role: Role, limit: Int, offset: Int): [User!]!
36    user(id: ID!): User
37    posts(published: Boolean, search: String, limit: Int): [Post!]!
38    post(id: ID!): Post
39  }
40
41  input CreatePostInput {
42    title: String!
43    content: String
44    tags: [String!]
45    published: Boolean
46  }
47
48  input UpdatePostInput {
49    title: String
50    content: String
51    tags: [String!]
52    published: Boolean
53  }
54
55  type Mutation {
56    createPost(input: CreatePostInput!): Post!
57    updatePost(id: ID!, input: UpdatePostInput!): Post!
58    deletePost(id: ID!): Boolean!
59    register(name: String!, email: String!, password: String!): AuthPayload!
60    login(email: String!, password: String!): AuthPayload!
61  }
62
63  type AuthPayload {
64    token: String!
65    user: User!
66  }
67
68  type Query {
69    users(role: Role, limit: Int, offset: Int): [User!]!
70    user(id: ID!): User
71    posts(published: Boolean, search: String, limit: Int): [Post!]!
72    post(id: ID!): Post
73    me: User
74  }
75`;
76
77// Mock data
78const users = [
79  { id: "1", name: "Alice", email: "alice@example.com", role: "ADMIN", createdAt: new Date().toISOString() },
80  { id: "2", name: "Bob", email: "bob@example.com", role: "USER", createdAt: new Date().toISOString() },
81];
82
83const posts = [
84  { id: "1", title: "GraphQL Intro", content: "Learn GraphQL...", published: true, authorId: "1", tags: ["graphql"], createdAt: new Date().toISOString() },
85  { id: "2", title: "Node.js Tips", content: "Advanced Node...", published: true, authorId: "1", tags: ["nodejs"], createdAt: new Date().toISOString() },
86  { id: "3", title: "Draft", content: "WIP...", published: false, authorId: "2", tags: [], createdAt: new Date().toISOString() },
87];
88
89// 2. Resolvers
90const resolvers = {
91  Query: {
92    users: (_, { role, limit = 10, offset = 0 }) => {
93      let result = [...users];
94      if (role) result = result.filter((u) => u.role === role);
95      return result.slice(offset, offset + limit);
96    },
97    user: (_, { id }) => users.find((u) => u.id === id),
98    posts: (_, { published, search, limit = 10 }) => {
99      let result = [...posts];
100      if (published !== undefined) result = result.filter((p) => p.published === published);
101      if (search) {
102        const s = search.toLowerCase();
103        result = result.filter((p) => p.title.toLowerCase().includes(s));
104      }
105      return result.slice(0, limit);
106    },
107    post: (_, { id }) => posts.find((p) => p.id === id),
108  },
109
110  Mutation: {
111    createPost: (_, { input }, context) => {
112      const post = {
113        id: String(posts.length + 1),
114        ...input,
115        published: input.published || false,
116        tags: input.tags || [],
117        authorId: "1", // From auth context
118        createdAt: new Date().toISOString(),
119      };
120      posts.push(post);
121      return post;
122    },
123    updatePost: (_, { id, input }) => {
124      const index = posts.findIndex((p) => p.id === id);
125      if (index === -1) throw new Error("Post not found");
126      posts[index] = { ...posts[index], ...input };
127      return posts[index];
128    },
129    deletePost: (_, { id }) => {
130      const index = posts.findIndex((p) => p.id === id);
131      if (index === -1) throw new Error("Post not found");
132      posts.splice(index, 1);
133      return true;
134    },
135  },
136
137  // Field resolvers (for relationships)
138  User: {
139    posts: (user) => posts.filter((p) => p.authorId === user.id),
140    postCount: (user) => posts.filter((p) => p.authorId === user.id).length,
141  },
142
143  Post: {
144    author: (post) => users.find((u) => u.id === post.authorId),
145  },
146};
147
148// 3. Create and start server
149async function startServer() {
150  const server = new ApolloServer({ typeDefs, resolvers });
151  const { url } = await startStandaloneServer(server, { listen: { port: 4000 } });
152  console.log(`GraphQL server at ${url}`);
153}
154
155startServer();
156
157// 4. Example queries (for GraphQL playground)
158const exampleQueries = `
159# Get users with their posts
160query {
161  users {
162    id
163    name
164    posts {
165      title
166      published
167    }
168    postCount
169  }
170}
171
172# Create a post
173mutation {
174  createPost(input: {
175    title: "New Post"
176    content: "Content here"
177    tags: ["nodejs"]
178    published: true
179  }) {
180    id
181    title
182    author { name }
183  }
184}
185
186# Search posts
187query {
188  posts(search: "graphql", published: true) {
189    title
190    author { name email }
191    tags
192  }
193}
194`;