swc/bundler/tests/.cache/deno/0746b127cd90af92cf12b2ec02c10c123b75903c.ts

// Loaded from https://deno.land/x/graphql_deno@v15.0.0/lib/validation/rules/NoUnusedVariablesRule.js


import { GraphQLError } from '../../error/GraphQLError.js';

/**
 * No unused variables
 *
 * A GraphQL operation is only valid if all variables defined by an operation
 * are used, either directly or within a spread fragment.
 */
export function NoUnusedVariablesRule(context) {
  let variableDefs = [];
  return {
    OperationDefinition: {
      enter() {
        variableDefs = [];
      },

      leave(operation) {
        const variableNameUsed = Object.create(null);
        const usages = context.getRecursiveVariableUsages(operation);

        for (const {
          node
        } of usages) {
          variableNameUsed[node.name.value] = true;
        }

        for (const variableDef of variableDefs) {
          const variableName = variableDef.variable.name.value;

          if (variableNameUsed[variableName] !== true) {
            context.reportError(new GraphQLError(operation.name ? `Variable "$${variableName}" is never used in operation "${operation.name.value}".` : `Variable "$${variableName}" is never used.`, variableDef));
          }
        }
      }

    },

    VariableDefinition(def) {
      variableDefs.push(def);
    }

  };
}