Apollo client is a powerful frontend GraphQL library that allows an application using GraphQL to query itself, and the connected GraphQL data service. It is a client side state management library that integrates deeply with GraphQL backends.

Under the covers, Apollo client takes your GraphQL query response, and flattens it into a key-value storage system. Take the following example:

// GraphQL Query and Type
type Account { 
  id: ID!
  userName: String!
}
query getAccount() {
  account {
    id
    userName
    __typename // not required, but for illustration
  }  
}

The query above for a value on type Account, would return a response like this:

{
  data: {
    account: {
      id: 1,
      userName: 'user',
      __typename: 'Account'
    }
  }
}

#apollo #graphql #apollo-client #javascript #react