Graph QL

High level

1. When to use
   1. there is a lot of api request going on
   2. huge amount of traffit
2. Cons
   1. configuration need
   2. hard to debug
3. GraphQL Tools
4. REST vs GraphQL
   1. GraphQl has only endpoint, then response is based on query
   2. overfeching
   3. underfeching

Concept

1. Fields

   1. Meta fields
      1. __typename

2. Arguments

3. Aliases

4. Fragments¹

   1. var inside fragments
   2. inline fragments
      1. interfaces
      2. union

5. Operation name

   1. keyword - query, mutation, subscription
   2. query name

6. variables²

   1. definitions
      1. options !
   2. default value

7. directives

   1. @inlcude(if: Boolean)
   2. @skip(if: Boolean)

8. query

9. mutation

   1. inputObject

10. query vs mutation³

11. Schemas

    1. type system
    2. type language
    3. objec types and fileds
    4. nullable
       1. Episode!
       2. [Episode!]!
    5. Arguments

12. Types

    1. Query and muatatoin types
    2. Scalar types
       1. Int
       2. Float
       3. String
       4. Boolean
       5. ID
    3. Custom type
    4. Enum type
    5. Lists
    6. Non-Null

13. Interfaces

14. Union

15. Validation

16. Execution

    1. Root fields
    2. resolvers
       1. obj
       2. args
       3. context
       4. info
    3. async resolvers
    4. trivial resolvers
    5. list resolveres
    6. scalar coercion

17. Schema

    1. type
       1. ID
       2. String
       3. [String]
    2. constans
       1. ! - compelsory
    3. enum
    4. input
    5. Query
       1. ResolveFeild
       2. nullable
    6. Mutation
       1. Args
       2. InputType

18. [^4]Resolves

19. Arguments

20. Apollo

21. NestJS

    1. schema first approch
    2. code first approch
    3. Resolve field

Links

GraphQL in NestJS

Footnotes

1. That’s why GraphQL includes reusable units called fragments. Fragments let you construct sets of fields, and then include them in queries where you need to ↩

2. GraphQL has a first-class way to factor dynamic values out of the query, and pass them as a separate dictionary. These values are called variables. ↩

3. While query fields are executed in parallel, mutation fields run in series, one after the other. ↩