GraphQL

[!TIP]

Just for those curious minds who always jump from one branch to another like mine:

• Hasura
• GraphQL VS REST.
• Testing GraphQL API

You can find a good definition usually in glossary.

1. Intro.
2. Data types.
3. A simple todo app written with GraphQL + ReactJS + Relay:
   • Backend.
   • Frontend TK.
4. Queries and mutations in depth.
5. Let’s breakdown the query language a bit more.
6. Functions provided by graphql.
7. Document your GraphQL service API.
8. GraphQL request lifecycle.
   • Common validation errors.
   • Execution from inside, resolver’s args, AST, …
9. Code-first approach.
10. Auth.
11. How to query information about a GraphQL schema.
12. Improve developer experience.
    • IoC – Inversion of Control principle.
    • Use a schema.graphql file
    • Strongly typed resolvers, context, ….
    • Filtering using prisma-nestjs-graphql.
    • Use exported enum from Prisma.
13. Security in GraphQL.
14. NestJS.
    • Query complexity.
    • Query depth and complexity in one package.
    • Write E2E tests for GraphQL.
    • Nested field validation with class-validator in a GraphQL mutation.
    • In GraphQL we do not have union types, instead:
      • You can use @oneOf directive, learn more about it here.
      • Here is a working example which is using @oneOf decorator.
      • A workaround if you are using an old version of @nestjs/graphql you can look at testOneOf API.

      🛑 Caution

      This directive won’t allow you to send both fields at the same time. E.g. in our CreateTemplateInput you can only specify either html or css. I.e. this query will fail with OneOf Input Object \"CreateTemplateInput\" must specify exactly one key.:

      mutation {
        createTemplate(
          input: {
            css: { template: "body { color: red }" }
            html: {
              styleIds: []
              subject: "some"
              template: "html"
            }
          }
        ) {
          id
        }
      }
      

15. Subscription.
16. Best practices.
    • Serve over HTTP.
    • Compress your request/response with GZIP.
    • Avoid versioning.
    • Most of the times fields are nullable.
    • Pagination.
    • Communication with a GraphQL service.
    • Batching.
    • Caching.