eslint-plugin-ember/lib/rules/no-side-effects.js

Eslint plugin for Ember.js apps

'use strict';

const utils = require('../utils/utils');
const ember = require('../utils/ember');

//------------------------------------------------------------------------------
// General rule - Don't introduce side-effects in computed properties
//------------------------------------------------------------------------------

module.exports = {
  meta: {
    docs: {
      description: 'Warns about unexpected side effects in computed properties',
      category: 'Possible Errors',
      recommended: true,
      url: 'https://github.com/ember-cli/eslint-plugin-ember/tree/master/docs/rules/no-side-effects.md'
    },
    fixable: null, // or "code" or "whitespace"
  },

  create(context) {
    let emberImportAliasName;

    const message = 'Don\'t introduce side-effects in computed properties';

    const report = function (node) {
      context.report(node, message);
    };

    return {
      ImportDeclaration(node) {
        if (!emberImportAliasName) {
          emberImportAliasName = ember.getEmberImportAliasName(node);
        }
      },

      CallExpression(node) {
        const callee = node.callee;
        const isEmberSet = (
          utils.isIdentifier(callee) &&
          callee.name === 'set'
        ) || (
          utils.isMemberExpression(callee) &&
          (utils.isThisExpression(callee.object) || callee.object.name === 'Ember' || callee.object.name === emberImportAliasName) &&
          utils.isIdentifier(callee.property) &&
          callee.property.name === 'set'
        );

        if (isEmberSet) {
          const ancestors = context.getAncestors();
          const computedIndex = ancestors.findIndex(ember.isComputedProp);
          const setPropertyFunctionIndex = ancestors.findIndex(ancestor => (
            ancestor.type === 'Property' &&
            ancestor.key.name === 'set' &&
            utils.isFunctionExpression(ancestor.value)
          ));

          if (
            computedIndex > -1 &&
            (setPropertyFunctionIndex === -1 || setPropertyFunctionIndex < computedIndex)
          ) {
            report(node);
          }
        }
      },
    };
  }
};