Task: support json field

[roneli]

This pull request introduces comprehensive support for working with PostgreSQL JSONB columns in FastGQL, including a new @json directive for typed JSON fields, efficient nested field selection, and advanced filtering capabilities. The changes add documentation, example code, and database setup to demonstrate these features, making it much easier to query and filter JSON data in a type-safe and performant way.

JSON Field Selection and Filtering Enhancements

• Added the @json directive for marking GraphQL fields as typed JSON stored in PostgreSQL JSONB columns, enabling type-safe filtering and efficient nested field selection in queries. Documentation now explains both the directive and its usage, with examples for both typed and dynamic JSON approaches. [1] [2]
• Introduced detailed documentation and examples for selecting nested fields from JSON columns, including setup instructions, test queries, and expected results. This covers scalar selection, deep nesting, and mixed queries, with clear explanations of how FastGQL leverages PostgreSQL operators for performance. [1] [2]

JSON Filtering Operators

• Documented specialized filtering operators for JSON fields, including the MapComparator input type for dynamic JSON and the MapPathCondition for JSONPath-based filtering. Examples and validation rules for JSON paths are provided, covering containment, path-based conditions, and null checks. [1] [2]

Example Setup and Supporting Files

• Added a complete example in the examples/json/ directory, including SQL schema and test data for products with JSONB columns, GraphQL schema definitions, README with setup and queries, and configuration files for code generation and GraphQL tooling. [1] [2] [3] [4] [5]

These changes provide a robust foundation for working with JSONB columns in FastGQL, making it easy to define, query, and filter structured and dynamic JSON data directly from your GraphQL API.

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Project	Deployment	Review	Updated (UTC)
fastgql-by75	Ready	Preview, Comment	Dec 27, 2025 7:21pm

[Copilot]

Pull request overview

This PR introduces comprehensive support for working with PostgreSQL JSONB columns in FastGQL, enabling type-safe filtering and efficient nested field selection for JSON data through the new @json directive.

Key Changes:

• Added @json directive for typed JSON fields with automatic filter input generation
• Implemented JSONPath-based filtering for dynamic JSON using MapComparator and MapPathCondition
• Created efficient nested field selection using PostgreSQL's native -> operator and jsonb_build_object

Reviewed changes

Copilot reviewed 36 out of 40 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
pkg/schema/fastgql.graphql	Added @json directive definition, IDComparator, MapComparator, and MapPathCondition input types
pkg/schema/schema.go	Added jsonDirectiveName constant for directive registration
pkg/schema/fastgql.go	Registered @json directive in FastGQLDirectives list
pkg/schema/filter.go	Implemented filter input generation for JSON types with createJsonTypeFilterInput function
pkg/schema/filter_test.go	Added comprehensive test coverage for JSON filter generation
pkg/execution/builders/sql/json.go	Implemented JSONPath expression building, path validation, and field selection logic
pkg/execution/builders/sql/json_test.go	Added extensive test coverage for JSON filtering and path validation
pkg/execution/builders/sql/builder.go	Integrated JSON field building and filtering into query builder
pkg/execution/builders/sql/builder_test.go	Added tests for JSON filtering and field selection SQL generation
pkg/execution/builders/field.go	Added TypeJson field type for JSON fields
pkg/execution/e2e_test.go	Added E2E tests for typed and Map JSON filtering
examples/json/*	Complete example with schema, SQL setup, resolvers, and documentation
docs/src/content/docs/schema/directives.md	Documented @json directive with usage examples
docs/src/content/docs/schema/operators.md	Documented MapComparator and MapPathCondition operators
docs/src/content/docs/queries/queries.md	Added JSON field selection documentation
docs/src/content/docs/queries/filtering.mdx	Added comprehensive JSON filtering documentation with examples

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[Copilot]

Pull request overview

Copilot reviewed 41 out of 47 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

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