我已经按照留档使用graph ql-tools来模拟GraphQL服务器，但是这会引发自定义类型的错误，例如：

Expected a value of type "JSON" but received: [object Object]

关于mocking的graph ql-tools留档明确声明它们支持自定义类型，甚至提供了一个使用graph ql-type-json项目中的GraphQLJSON自定义类型的示例。

我在github上提供了一个解决方案的演示，该解决方案使用graph ql-tools成功模拟GraphQL服务器，但这依赖于对构建的模式进行猴子修补：

// Here we Monkey-patch the schema, as otherwise it will fall back
// to the default serialize which simply returns null.
schema._typeMap.JSON._scalarConfig.serialize = () => {
    return { result: 'mocking JSON monkey-patched' }
}

schema._typeMap.MyCustomScalar._scalarConfig.serialize = () => {
    return mocks.MyCustomScalar()
}

可能我在演示中做错了什么，但是如果没有上面的猴子补丁代码，我就会得到上面提到的自定义类型的错误。

是否有人有比我的演示更好的解决方案，或者关于我可能做错了什么的任何线索，以及如何更改代码以使演示在不对架构进行猴子修补的情况下工作？

demoindex. js中的相关代码如下：

/*
** As per:
** http://dev.apollodata.com/tools/graphql-tools/mocking.html
** Note that there are references on the web to graphql-tools.mockServer,
** but these seem to be out of date.
*/

const { graphql, GraphQLScalarType } = require('graphql');
const { makeExecutableSchema, addMockFunctionsToSchema } = require('graphql-tools');
const GraphQLJSON = require('graphql-type-json');

const myCustomScalarType = new GraphQLScalarType({
  name: 'MyCustomScalar',
  description: 'Description of my custom scalar type',
  serialize(value) {
    let result;
    // Implement your own behavior here by setting the 'result' variable
    result = value || "I am the results of myCustomScalarType.serialize";
    return result;
  },
  parseValue(value) {
    let result;
    // Implement your own behavior here by setting the 'result' variable
    result = value || "I am the results of myCustomScalarType.parseValue";
    return result;
  },
  parseLiteral(ast) {
    switch (ast.kind) {
      // Implement your own behavior here by returning what suits your needs
      // depending on ast.kind
    }
  }
});

const schemaString = `
    scalar MyCustomScalar
    scalar JSON

    type Foo {
        aField: MyCustomScalar
        bField: JSON
        cField: String
    }

    type Query {
        foo: Foo
    }
`;
const resolverFunctions = {
    Query: {
        foo: {
            aField: () => {
                return 'I am the result of resolverFunctions.Query.foo.aField'
            },
            bField: () => ({ result: 'of resolverFunctions.Query.foo.bField' }),
            cField: () => {
                return 'I am the result of resolverFunctions.Query.foo.cField'
            }
        },
    },
};

const mocks = {
    Foo: () => ({
        // aField: () => mocks.MyCustomScalar(),
        // bField: () => ({ result: 'of mocks.foo.bField' }),
        cField: () => {
            return 'I am the result of mocks.foo.cField'
        }
    }),

    cField: () => {
        return 'mocking cField'
    },

    MyCustomScalar: () => {
        return 'mocking MyCustomScalar'
    },

    JSON: () => {
        return { result: 'mocking JSON'}
    }
}

const query = `
{
  foo {
      aField
      bField
      cField
  }
}
`;

const schema = makeExecutableSchema({
    typeDefs: schemaString,
    resolvers: resolverFunctions
})

addMockFunctionsToSchema({
    schema,
    mocks
});

// Here we Monkey-patch the schema, as otherwise it will fall back
// to the default serialize which simply returns null.
schema._typeMap.JSON._scalarConfig.serialize = () => {
    return { result: 'mocking JSON monkey-patched' }
}

schema._typeMap.MyCustomScalar._scalarConfig.serialize = () => {
    return mocks.MyCustomScalar()
}

graphql(schema, query).then((result) => console.log('Got result', JSON.stringify(result, null, 4)));