====== Notes ======
  * One endpoint `/graphql`
    * Query 
    * Mutation
    * Subscription 
  * Return type
    * Enums are useful 

<code>
enum PhotoCategory {
  PORTRAIT
  ACTION
  TEST
}
</code>

Aliasing a query:
<code>
query {
  alias : totalPets(status:AVAILABLE)
}
</code>

Neat link

  * https://developer.github.com/v4/explorer/




Handling multiple behaviours for a single endpoint

  * array of options, filters... handle on the server 


Dont forget you can put two queries in one: 

<code>
query{
  query1{...}
  query2{...}
}
</code>

graphql scalar type

  * Int 
  * Float 
  * String
  * Boolean
  * ID

Nullable  vs non nullable

<code>
name: String!
</code>

<code>
description: String
</code>



Nullable list of nullable values
<code>
photos: [Photo]
</code>

non-Nullable list of nullable values
<code>
photos: [Photo]!
</code>

non-Nullable list of non-nullable values
<code>
photos: [Photo!]!
</code>


Mutations
  * ~should~ always return atleast something

<code>
type mutation{
  get(): Boolean!
}
</code>


===== Custom Scalar =====

Things that arent gonna be a custom scalar, it will probably be an custom ENUM 

<code>

scalar DateTime

type Photo {
  created: DateTime!
  updated: DateTime!
}</code>

[[https://raw.githubusercontent.com/sogko/graphql-shorthand-notation-cheat-sheet/master/graphql-shorthand-notation-cheat-sheet.png]]


===== MOCK: TRUE -- Super useful  =====
const server = new ApolloServer({
    typeDefs,
    resolvers,
    mocks: true // TODO -- super handy
});



===== Documentation =====


<code>
"""
Triple double-quote for the type. This is doc for the type
"""
type X {
  "Single double-quote for the field"
  field: ID!
}
</code>


===== Interface and misc =====

returns the typename for the field
<code>__typename</code>


<code>...on </code>
<code>
type pet{
  id
  name
  weight
  ...on Cat{
    curious
  }
  ...on Stingray{
    stingy
  }
}
</code>


===== resolvers =====

resolvers are used to get data wherever it is


===== Maybe give some info on ApolloClient =====


Apollo dev tool (chrome + firefox addon)

  * shows schema + graphiql 
  * displays cached data 
  * root query 


How are you supposed to use subscriptions? should they return data or no?