使用 GraphQL 模擬伺服器很容易

// > npm install graphql-tools
import { mockServer } from "graphql-tools"
import schema from "./mySchema.graphql"

const myMockServer = mockServer(schema)
myMockServer.query(`{
  allUsers: {
    id
    name
  }
}`)

// returns
// {
//   data: {
//     allUsers:[
//       { id: 'ee5ae76d-9b91-4270-a007-fad2054e2e75', name: 'lorem ipsum' },
//       { id: 'ca5c182b-99a8-4391-b4b4-4a20bd7cb13a', name: 'quis ut' }
//     ]
//   }
// }

// customize mocking per type (i.e. Integer, Float, String)
mockServer(schema, {
  Int: () => 6,
  Float: () => 22.1,
  String: () => 'Hello',
});

// customize mocking per field in the schema (i.e. for Person.name and Person.age)
mockServer(schema, {
  Person: () => ({
    name: casual.name,
    age: () => casual.integer(0,120),
  })
});

// mock lists of specific or random length( and lists of lists of lists …)
mockServer(schema, {
  Person: () => {
    // a list of length between 2 and 6
    friends: () => new MockList([2,6]),
    // a list of three lists of two items: [[1, 1], [2, 2], [3, 3]]
    listOfLists: () => new MockList(3, () => new MockList(2)),
  },
});

// customize mocking of a field or type based on the query arguments
mockServer(schema, {
  Person: () => {
    // the number of friends in the list now depends on numPages
    paginatedFriends: (o, { numPages }) => new MockList(numPages * PAGE_SIZE),
  },
});

// You can also disable mocking for specific fields, pass through to the backend, etc.

import { mockServer, MockList } from "graphql-tools"
import casual from "casual-browserify"

// The GraphQL schema. Described in more detail here:
// https://medium.com/apollo-stack/the-apollo-server-bc68762e93b
const schema = `
  type User {
    id: ID!
    name: String
    lists: [List]
  }
  type List {
    id: ID!
    name: String
    owner: User
    incomplete_count: Int
    tasks(completed: Boolean): [Task]
  }
  type Task {
    id: ID!
    text: String
    completed: Boolean
    list: List
  }
  type RootQuery {
    user(id: ID): User
  }
  schema {
    query: RootQuery
  }
`

// Mock functions are defined per type and return an
// object with some or all of the fields of that type.
// If a field on the object is a function, that function
// will be used to resolve the field if the query requests it.
const server = mockServer(schema, {
  RootQuery: () => ({
    user: (o, { id }) => ({ id }),
  }),
  List: () => ({
    name: () => casual.word,
    tasks: () => new MockList(4, (o, { completed }) => ({ completed })),
  }),
  Task: () => ({ text: casual.words(10) }),
  User: () => ({ name: casual.name }),
})

mockServer.query(`
query tasksForUser{
  user(id: 6) {
    id
    name
    lists {
      name
      completeTasks: tasks(completed: true) {
        completed
        text
      }
      incompleteTasks: tasks(completed: false) {
        completed
        text
      }
      anyTasks: tasks {
        completed
        text
      }
    }
  }
}`)