enforce-private-props.js

/**
 * Copyright 2018 The Subscribe with Google Authors. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS-IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
'use strict';

module.exports = function (context) {
  /**
   * @param {!Array<!Node>|undefined} commentLines
   * @return {boolean}
   */
  function hasPrivateAnnotation(commentLines) {
    if (!commentLines) {
      return false;
    }
    return commentLines.some(function (comment) {
      return comment.type == 'Block' && /@private/.test(comment.value);
    });
  }

  /**
   * @param {string}
   * @return {boolean}
   */
  function hasTrailingUnderscore(fnName) {
    return /_$/.test(fnName);
  }

  /**
   * @param {string}
   * @return {boolean}
   */
  function hasExplicitNoInline(fnName) {
    return /NoInline$/.test(fnName);
  }

  /**
   * @param {!Node}
   * @return {boolean}
   */
  function isThisMemberExpression(node) {
    return (
      node.type == 'MemberExpression' && node.object.type == 'ThisExpression'
    );
  }
  return {
    MethodDefinition: function (node) {
      if (
        hasPrivateAnnotation(node.leadingComments) &&
        !hasExplicitNoInline(node.key.name) &&
        !hasTrailingUnderscore(node.key.name)
      ) {
        context.report(
          node,
          'Method marked as private but has no trailing underscore.'
        );
      }
    },
    AssignmentExpression: function (node) {
      if (
        node.parent.type == 'ExpressionStatement' &&
        hasPrivateAnnotation(node.parent.leadingComments) &&
        isThisMemberExpression(node.left) &&
        !hasExplicitNoInline(node.left.property.name) &&
        !hasTrailingUnderscore(node.left.property.name)
      ) {
        context.report(
          node,
          'Property marked as private but has no trailing underscore.'
        );
      }
    },
  };
};