@redocly/openapi-core/src/rules/arazzo/requestBody-replacements-unique.ts

See https://github.com/Redocly/redocly-cli

import type { Arazzo1Rule } from '../../visitors';
import type { UserContext } from '../../walk';

export const RequestBodyReplacementsUnique: Arazzo1Rule = () => {
  const seenReplacements = new Set();

  return {
    Step: {
      leave() {
        seenReplacements.clear();
      },
      RequestBody: {
        enter(requestBody, { report, location }: UserContext) {
          if (!requestBody.replacements) return;

          for (const replacement of requestBody.replacements) {
            if (seenReplacements.has(replacement.target)) {
              report({
                message: 'Every `replacement` in `requestBody` must be unique.',
                location: location.child([
                  'replacements',
                  requestBody.replacements.indexOf(replacement),
                  `target`,
                ]),
              });
            }
            seenReplacements.add(replacement.target);
          }
        },
      },
    },
  };
};