@graphql-eslint/eslint-plugin/esm/rules/require-nullable-fields-with-oneof.js

GraphQL plugin for ESLint

import { Kind } from 'graphql';
const RULE_ID = 'require-nullable-fields-with-oneof';
export const rule = {
    meta: {
        type: 'suggestion',
        docs: {
            category: 'Schema',
            description: 'Require `input` or `type` fields to be non-nullable with `@oneOf` directive.',
            url: `https://github.com/B2o5T/graphql-eslint/blob/master/docs/rules/${RULE_ID}.md`,
            examples: [
                {
                    title: 'Incorrect',
                    code: /* GraphQL */ `
            input Input @oneOf {
              foo: String!
              b: Int
            }
          `,
                },
                {
                    title: 'Correct',
                    code: /* GraphQL */ `
            input Input @oneOf {
              foo: String
              bar: Int
            }
          `,
                },
            ],
        },
        messages: {
            [RULE_ID]: 'Field `{{fieldName}}` must be nullable.',
        },
        schema: [],
    },
    create(context) {
        return {
            'Directive[name.value=oneOf]'({ parent, }) {
                const isTypeOrInput = [
                    Kind.OBJECT_TYPE_DEFINITION,
                    Kind.INPUT_OBJECT_TYPE_DEFINITION,
                ].includes(parent.kind);
                if (!isTypeOrInput) {
                    return;
                }
                for (const field of parent.fields) {
                    if (field.gqlType.kind === Kind.NON_NULL_TYPE) {
                        context.report({
                            node: field.name,
                            messageId: RULE_ID,
                            data: { fieldName: field.name.value },
                        });
                    }
                }
            },
        };
    },
};