@ardatan/relay-compiler/lib/transforms/SkipUnusedVariablesTransform.js

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/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 *
 * @format
 */
// flowlint ambiguous-object-type:error
'use strict';

var _interopRequireDefault = require('@babel/runtime/helpers/interopRequireDefault');

var _objectSpread2 = _interopRequireDefault(require('@babel/runtime/helpers/objectSpread2'));

var _createForOfIteratorHelper2 = _interopRequireDefault(
  require('@babel/runtime/helpers/createForOfIteratorHelper'),
);

var inferRootArgumentDefinitions = require('../core/inferRootArgumentDefinitions');

/**
 * Refines the argument definitions for operations to remove unused arguments
 * due to statically pruned conditional branches (e.g. because of overriding
 * a variable used in `@include()` to be false).
 */
function skipUnusedVariablesTransform(context) {
  var contextWithUsedArguments = inferRootArgumentDefinitions(context);
  return context.withMutations(function (ctx) {
    var nextContext = ctx;

    var _iterator = (0, _createForOfIteratorHelper2['default'])(nextContext.documents()),
      _step;

    try {
      var _loop = function _loop() {
        var node = _step.value;

        if (node.kind !== 'Root') {
          return 'continue';
        }

        var usedArguments = new Set(
          contextWithUsedArguments.getRoot(node.name).argumentDefinitions.map(function (argDef) {
            return argDef.name;
          }),
        ); // Remove unused argument definitions

        var usedArgumentDefinitions = node.argumentDefinitions.filter(function (argDef) {
          return usedArguments.has(argDef.name);
        });

        if (usedArgumentDefinitions.length !== node.argumentDefinitions.length) {
          nextContext = nextContext.replace(
            (0, _objectSpread2['default'])(
              (0, _objectSpread2['default'])({}, node),
              {},
              {
                argumentDefinitions: usedArgumentDefinitions,
              },
            ),
          );
        }
      };

      for (_iterator.s(); !(_step = _iterator.n()).done; ) {
        var _ret = _loop();

        if (_ret === 'continue') continue;
      }
    } catch (err) {
      _iterator.e(err);
    } finally {
      _iterator.f();
    }

    return nextContext;
  });
}

module.exports = {
  transform: skipUnusedVariablesTransform,
};