Question

By using graphql-js, I need to create graphql schema dynamically by iterating over array of some data, for example:

[{
    name: 'author',
    fields: [{
        field: 'name'
    }, {
        field: 'books',
        reference: 'book'
    }]
}, {
    name: 'book',
    fields: [{
        field: 'title'
    }, {
        field: 'author',
        reference: 'author'
    }]
}]

The problem is circular references. When I'm creating AuthorType I need BookType to be already created and vise versa.

So resulting schema should look like:

type Author : Object {  
  id: ID!
  name: String,
  books: [Book]
}

type Book : Object {  
  id: ID!
  title: String
  author: Author
}

How can I solve this?

Answer 1

引自官方文件

http://graphql.org/docs/api-reference-type-system/

当两种类型需要相互引用时，或者需要引用类型时在字段中，您可以使用函数表达式（也称为闭包）或者是一个懒洋洋的人来懒洋洋地供应田地。

a1=cell2mat(final(:,3)); %numeric data, variable 1 to save
no=cell2mat(final(:,4));
a2=zeros(numel(a1),1); %temporary variable
for i=1:numel(a2);
   if no(i)~=1;
      a2(i)=no(i); 
   end
end
a3=a1+a2; %numeric data, variable 2 to save

fid = fopen( 'results.txt', 'wt' );
for i=1:length(no);
    fprintf(fid, '%f  %f  %s\n',a1(i),a3(i),char(final(i,2)));
end
fclose(fid);

另请参阅循环类别 - 子类别

的相关answer

Answer 2

我通过在字段字段中使用thunk解决了这个问题。

const User = new GraphQLObjectType({
  name: 'User',
  fields: () => ({
    id: { type: GraphQLID }
  })
});

当您将字段设置为thunk而不是对象文字时，可以使用稍后在文件中定义的类型。

请参阅此帖子了解更多信息Is there a way to avoid circular type dependencies in GraqhQL?

基于该帖子，我认为这是正确的方法。

Dynamically creating graphql schema with circular references

2 个答案: