@graphql-eslint/eslint-plugin/esm/rules/relay-connection-types/index.js

GraphQL plugin for ESLint

import { Kind } from "graphql";
const MUST_BE_OBJECT_TYPE = "MUST_BE_OBJECT_TYPE";
const MUST_CONTAIN_FIELD_EDGES = "MUST_CONTAIN_FIELD_EDGES";
const MUST_CONTAIN_FIELD_PAGE_INFO = "MUST_CONTAIN_FIELD_PAGE_INFO";
const MUST_HAVE_CONNECTION_SUFFIX = "MUST_HAVE_CONNECTION_SUFFIX";
const EDGES_FIELD_MUST_RETURN_LIST_TYPE = "EDGES_FIELD_MUST_RETURN_LIST_TYPE";
const PAGE_INFO_FIELD_MUST_RETURN_NON_NULL_TYPE = "PAGE_INFO_FIELD_MUST_RETURN_NON_NULL_TYPE";
const NON_OBJECT_TYPES = [
  Kind.SCALAR_TYPE_DEFINITION,
  Kind.UNION_TYPE_DEFINITION,
  Kind.UNION_TYPE_EXTENSION,
  Kind.INPUT_OBJECT_TYPE_DEFINITION,
  Kind.INPUT_OBJECT_TYPE_EXTENSION,
  Kind.ENUM_TYPE_DEFINITION,
  Kind.ENUM_TYPE_EXTENSION,
  Kind.INTERFACE_TYPE_DEFINITION,
  Kind.INTERFACE_TYPE_EXTENSION
];
const notConnectionTypesSelector = `:matches(${NON_OBJECT_TYPES})[name.value=/Connection$/] > .name`;
const hasEdgesField = (node) => node.fields?.some((field) => field.name.value === "edges");
const hasPageInfoField = (node) => node.fields?.some((field) => field.name.value === "pageInfo");
const rule = {
  meta: {
    type: "problem",
    docs: {
      category: "Schema",
      description: [
        "Set of rules to follow Relay specification for Connection types.",
        "",
        '- Any type whose name ends in "Connection" is considered by spec to be a `Connection type`',
        "- Connection type must be an Object type",
        "- Connection type must contain a field `edges` that return a list type that wraps an edge type",
        "- Connection type must contain a field `pageInfo` that return a non-null `PageInfo` Object type"
      ].join("\n"),
      url: "https://the-guild.dev/graphql/eslint/rules/relay-connection-types",
      isDisabledForAllConfig: true,
      examples: [
        {
          title: "Incorrect",
          code: (
            /* GraphQL */
            `
            type UserPayload { # should be an Object type with \`Connection\` suffix
              edges: UserEdge! # should return a list type
              pageInfo: PageInfo # should return a non-null \`PageInfo\` Object type
            }
          `
          )
        },
        {
          title: "Correct",
          code: (
            /* GraphQL */
            `
            type UserConnection {
              edges: [UserEdge]
              pageInfo: PageInfo!
            }
          `
          )
        }
      ]
    },
    messages: {
      // Connection types
      [MUST_BE_OBJECT_TYPE]: "Connection type must be an Object type.",
      [MUST_HAVE_CONNECTION_SUFFIX]: "Connection type must have `Connection` suffix.",
      [MUST_CONTAIN_FIELD_EDGES]: "Connection type must contain a field `edges` that return a list type.",
      [MUST_CONTAIN_FIELD_PAGE_INFO]: "Connection type must contain a field `pageInfo` that return a non-null `PageInfo` Object type.",
      [EDGES_FIELD_MUST_RETURN_LIST_TYPE]: "`edges` field must return a list type.",
      [PAGE_INFO_FIELD_MUST_RETURN_NON_NULL_TYPE]: "`pageInfo` field must return a non-null `PageInfo` Object type."
    },
    schema: []
  },
  create(context) {
    return {
      [notConnectionTypesSelector](node) {
        context.report({ node, messageId: MUST_BE_OBJECT_TYPE });
      },
      ":matches(ObjectTypeDefinition, ObjectTypeExtension)[name.value!=/Connection$/]"(node) {
        if (hasEdgesField(node) && hasPageInfoField(node)) {
          context.report({ node: node.name, messageId: MUST_HAVE_CONNECTION_SUFFIX });
        }
      },
      ":matches(ObjectTypeDefinition, ObjectTypeExtension)[name.value=/Connection$/]"(node) {
        if (!hasEdgesField(node)) {
          context.report({ node: node.name, messageId: MUST_CONTAIN_FIELD_EDGES });
        }
        if (!hasPageInfoField(node)) {
          context.report({ node: node.name, messageId: MUST_CONTAIN_FIELD_PAGE_INFO });
        }
      },
      ":matches(ObjectTypeDefinition, ObjectTypeExtension)[name.value=/Connection$/] > FieldDefinition[name.value=edges] > .gqlType"(node) {
        const isListType = node.kind === Kind.LIST_TYPE || node.kind === Kind.NON_NULL_TYPE && node.gqlType.kind === Kind.LIST_TYPE;
        if (!isListType) {
          context.report({ node, messageId: EDGES_FIELD_MUST_RETURN_LIST_TYPE });
        }
      },
      ":matches(ObjectTypeDefinition, ObjectTypeExtension)[name.value=/Connection$/] > FieldDefinition[name.value=pageInfo] > .gqlType"(node) {
        const isNonNullPageInfoType = node.kind === Kind.NON_NULL_TYPE && node.gqlType.kind === Kind.NAMED_TYPE && node.gqlType.name.value === "PageInfo";
        if (!isNonNullPageInfoType) {
          context.report({ node, messageId: PAGE_INFO_FIELD_MUST_RETURN_NON_NULL_TYPE });
        }
      }
    };
  }
};
export {
  NON_OBJECT_TYPES,
  rule
};