Apollo GraphQL Error: Query root type must be provided

I have an Angular/Apollo GraphQL implementation generating typescript code based on GraphQl endpoint which is surfacing a schema. I can hit the endpoint via Postman with a query and results are returned. However, when I run "graphql-codegen --config codegen.yml" via npm I get this error:

"Error: Query root type must be provided"

The server side is .Net Core implementation using GraphQL ASPNetCore. I have 4 different queries defined and each one works via graphiql.

Any ideas on why query root type is now being returned as null?

GraphQL must have at least one @Query() to be considered valid. So maybe only need add any Query to your Resolver code will be helpful.
Ex:

export class FooResolver {

  @Query(() => String)
  sayHello(): string {
    return 'Hello World!';
  }
}

</details>



# 答案2
**得分**: 1

这个错误是在您的模式拼接/定义不正确时引发的。请检查您的根模式定义。

链接：https://www.advancedgraphql.com/content/schema-stitching

<details>
<summary>英文:</summary>

This error throws when your schema stiching/definitions are incorrect. Please check the check your root schema definitions


https://www.advancedgraphql.com/content/schema-stitching

</details>



# 答案3
**得分**: 1

I was having the same issue while using `graphql-codegen`.

my codegen.yml is

overwrite: true
schema: "http://localhost:3001/graphql"
documents: "src/app/graphql/*.graphql"
generates:
src/generated/graphql.ts:
plugins:
- typescript
- typescript-operations
- typescript-apollo-angular

The issue was coming when I used the plugin `typescript-apollo-angular`.

I'm using `Nodejs` with `graphql` as backend.

The issue got resolved when I renamed the type
RootQuery -> Query
and
RootMutation -> Mutation
in backend **schema**.

Before

type RootQuery {
_empty: String
}

type RootMutation {
_empty: String
}

schema {
query: RootQuery
mutation: RootMutation
}

After

```javascript
type Query {
  _empty: String  
}

type Mutation {
  _empty: String
}

schema {
    query: Query
    mutation: Mutation
}

overwrite: true
schema: "http://localhost:3001/graphql"
documents: "src/app/graphql/*.graphql"
generates:
  src/generated/graphql.ts:
    plugins:
      - typescript
      - typescript-operations
      - typescript-apollo-angular

type RootQuery {
  _empty: String  
}

type RootMutation {
  _empty: String
}

schema {
    query: RootQuery
    mutation: RootMutation
}

type Query {
  _empty: String  
}

type Mutation {
  _empty: String
}

schema {
    query: Query
    mutation: Mutation
}

答案4

得分: 0

我最终还原到了代码库的先前版本，并手动重新应用了我的修改，现在它可以工作了。我唯一能想到的是我运行了npm update，将apollo-angular从1.8.3更新到了1.10.0。

编辑 这是我的代码：

codegen.yml（用于从npm命令生成代码的配置）：

overwrite: true
schema: "https://to_end_point/Prod/api/v1/GraphQL"
documents: "src/**/*.graphql"
generates:
  src/generated/graphql.ts:
    plugins:
      - "typescript"
      - "typescript-operations"
      - "typescript-apollo-angular"
  ./graphql.schema.json:
    plugins:
      - "introspection"

在还原到先前版本的Angular代码并重新应用我的代码修改后，GraphQL代码生成又可以工作了。我唯一能想到可能引起这个问题的是我运行npm update。以下是package.json的前后截图：

overwrite: true
schema: "https://to_end_point/Prod/api/v1/GraphQL"
documents: "src/**/*.graphql"
generates:
  src/generated/graphql.ts:
    plugins:
      - "typescript"
      - "typescript-operations"
      - "typescript-apollo-angular"
  ./graphql.schema.json:
    plugins:
      - "introspection"