@gatsbyjs/relay-compiler

Relay Compiler

Relay-Compiler is a code-generation toolkit for GraphQL. It contains the core functionalities of GraphQL code-gen, including file parsing, validation, syntax tree parsing and transformation.

The GraphQL-Compiler package exports library code which you may use to find the modules you need, or to extend the compiler with your own custom input and output. Note, the internal APIs of the GraphQL-Compiler are under constant iteration, so rolling your own version may lead to incompatibilities with future releases.

The following graph illustrates the high-level architecture of a complete GraphQL code-generation pipeline:

To understand the underlying workflow of the core compilation step, which is what happens in the "GraphQL Compiler" block in the above graph, please refer HERE.

You can build your own version of the Compiler by adding your own FileWriter, and by swapping or adding a FileParser and additional IRTransforms (IR, which stands for Intermediate Representation, a special-purpose syntax tree format designed for transformability).

• The GraphQL-Compiler package provides a GraphQLFileParser, which can be used to parse general .graphql files, and a GraphQLTextParser, which can be used to parse GraphQL text in any source files with customized tags. You can also write your own FileParser at your discretion.

• You can add additional IRTransforms by extending the basic GraphQLIRTransforms. A sample can be found HERE.

• Similarly, you can add additional validation rules by extending the basic GraphQLValidator. Sample HERE.

• A sample FileWriter can be found HERE.

To actually run your compiler, you will also need a script to assemble all the above components. A sample file can be found HERE.