react/scripts/eslint-rules/no-cross-fork-imports.js

/**
 * 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.
 *
 * @emails react-core
 */

'use strict';

function isOldFork(filename) {
  return filename.endsWith('.old.js') || filename.endsWith('.old');
}

function isNewFork(filename) {
  return filename.endsWith('.new.js') || filename.endsWith('.new');
}

module.exports = {
  meta: {
    type: 'problem',
    fixable: 'code',
  },
  create(context) {
    const sourceFilename = context.getFilename();

    if (isOldFork(sourceFilename)) {
      const visitor = node => {
        const sourceNode = node.source;
        if (sourceNode === null) {
          return;
        }
        const filename = sourceNode.value;
        if (isNewFork(filename)) {
          context.report({
            node: sourceNode,
            message:
              'A module that belongs to the old fork cannot import a module ' +
              'from the new fork.',
            fix(fixer) {
              return fixer.replaceText(
                sourceNode,
                `'${filename.replace(/\.new(\.js)?$/, '.old')}'`
              );
            },
          });
        }
      };
      return {
        ImportDeclaration: visitor,
        ExportNamedDeclaration: visitor,
      };
    }

    if (isNewFork(sourceFilename)) {
      const visitor = node => {
        const sourceNode = node.source;
        if (sourceNode === null) {
          return;
        }
        const filename = sourceNode.value;
        if (isOldFork(filename)) {
          context.report({
            node: sourceNode,
            message:
              'A module that belongs to the new fork cannot import a module ' +
              'from the old fork.',
            fix(fixer) {
              return fixer.replaceText(
                sourceNode,
                `'${filename.replace(/\.old(\.js)?$/, '.new')}'`
              );
            },
          });
        }
      };

      return {
        ImportDeclaration: visitor,
        ExportNamedDeclaration: visitor,
      };
    }

    return {};
  },
};