@relay-graphql-js/validation-rules/src/RelayKnownVariableNames.ts

shared relay validation rules for graphql-js parser

import type { ValidationRule } from "graphql";
import { GraphQLError } from "graphql";

import { getRecursiveVariableUsagesWithRelayInfo } from "./argumentDefinitions";

export function undefinedVarMessage(
  varName: string,
  opName: string | undefined,
  usingFragmentName: string | null
): string {
  opName = !opName ? "unnamed operation" : opName;
  return usingFragmentName
    ? `Variable "$${varName}" is used by fragment "${usingFragmentName}", but not defined by operation "${opName}".`
    : `Variable "$${varName}" is not defined by operation "${opName}".`;
}

// tslint:disable-next-line: no-shadowed-variable
export const RelayKnownVariableNames: ValidationRule = function RelayKnownVariableNames(context) {
  return {
    OperationDefinition(opDef) {
      const usages = getRecursiveVariableUsagesWithRelayInfo(context, opDef);

      const errors = Object.create(null);

      usages.forEach((usage) => {
        const varName = usage.node.name.value;
        if (!usage.variableDefinition) {
          const location = [...(!usage.usingFragmentName ? [usage.node] : []), opDef];
          const errorStr = undefinedVarMessage(varName, opDef.name && opDef.name.value, usage.usingFragmentName);
          if (!errors[errorStr]) {
            if (usage.usingFragmentName) {
              errors[errorStr] = true;
            }
            context.reportError(new GraphQLError(errorStr, location));
          }
        }
      });
    },
  };
};