Relay Internals

Relay Internals.md

Relay.QL transformation

• Relay.QL`... `
• -> babel-relay-plugin GraphQLPrinter
• -> A function that returns Relay GraphQL ('Query Builder')

Collecting queries

• RelayRootContainer (on mount)
  • getRelayQueries
    • buildRQL.Query -> GraphQL.Query
    • -> RelayQuery.Node.createQuery -> RelayQueryRoot

Subtracting queries

https://github.com/facebook/relay/blob/v0.1.1/src/traversal/subtractRelayQuery.js

If field is requisite, keep it (ex: id, ...)

Running queries

!forceFetch && no cache case

• RelayRootContainer (on mount)
  • -> RelayStore.primeCache
    • GraphQLQueryRunner.run
      • runQueries with fetchMode = CLIENT
        • splitAndFlattenQueries: splits deferred queries and then flatten
          • flattenRelayQuery: flattens nested fragments by giving aliases to fields (why do this? maybe optimization)
        • RelayPendingQueryTracker.add
          • subtractRelayQuery
          • fetchRelayQuery
            • _handleSubtractedQuerySucces
              • RelayStoreData.handleQueryPayload
                • writeRelayQueryPayload
                  • RelayNodeInterface.getResultsFromPayload:
                  • RelayQueryWriter.writePayload: traserve