express app to substitute middleware for ember-cli-code-coverage for use with ember-electron app

config.js

'use strict';

/**
 * @typedef {Object} Configuration
 * @property {String} coverageEnvVar - name of environment variable for coverage
 * @property {String} coverageFolder - directory in which to write coverage to
 * @property {Array<String>} excludes - list of glob paths to exclude
 * @property {Array<String>} reporters - list of reporters
 */

var extend = require('extend');
var fs = require('fs');
var path = require('path');

/**
 * Get configuration for a project, falling back to default configuration if
 * project does not provide a configuration of its own
 * @param {String} configPath - The path for the configuration of the project
 * @returns {Configuration} configuration to use for project
 */
function config(configPath) {
  var configDirName = path.dirname(configPath);
  var configFile = path.resolve(path.join(configDirName, 'coverage.js'));
  var defaultConfig = getDefaultConfig();

  if (fs.existsSync(configFile)) {
    var projectConfig = require(configFile);
    return extend({}, defaultConfig, projectConfig);
  }

  return defaultConfig;
}

/**
 * Get default configuration
 * @returns {Configuration} default configuration
 */
function getDefaultConfig() {
  return {
    coverageEnvVar: 'COVERAGE',
    coverageFolder: 'coverage',
    excludes: [
      '*/mirage/**/*'
    ],
    useBabelInstrumenter: false,
    // The reasoning behind this default is to match the default language version
    // supported by Ember CLI. As of Ember CLI 2.13, it supports ES2017.
    babelPlugins: [
      'babel-plugin-transform-async-to-generator'
    ],
    reporters: [
      'html',
      'lcov'
    ]
  };
}

module.exports = config;

index.js

const http = require('http'),
    path = require('path'),
    express = require('express'),
    bodyParser = require('body-parser'),
    cors = require('cors'),
    Istanbul = require('istanbul'),
    config = require('./config'),
    fs = require('fs-extra'),
    crypto = require('crypto');
    preflight = require('preflight');

// Create global app object
const app = express();
const options = {configPath: '/path/to/ember-electron/app/config', root:'/path/to/ember-electron/app'}

app.use(cors());
app.use(preflight());

// Normal express config defaults
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json({ limit: '500mb' }));

function logError(err, req, res, next) {
    console.error(err.stack);
    next(err);
}

app.get('/', (req, res) => {
    res.send('Hello World!')
});


app.post('/write-coverage',
    (req, res) => {
        const collector = new Istanbul.Collector();
        const _config = config(options.configPath);

        if (_config.parallel) {
            _config.coverageFolder = _config.coverageFolder + '_' + crypto.randomBytes(4).toString('hex');
            if (_config.reporters.indexOf('json') === -1) {
                _config.reporters.push('json');
            }
        }

        const reporter = new Istanbul.Reporter(null, path.join(options.root, _config.coverageFolder));
        const sync = true;

        collector.add(req.body);

        if (_config.reporters.indexOf('json-summary') === -1) {
            _config.reporters.push('json-summary');
        }

        reporter.addAll(_config.reporters);
        reporter.write(collector, sync, () => {
            const summaryFilePath = path.join(options.root, _config.coverageFolder, 'coverage-summary.json');
            const results = fs.readJSONSync(summaryFilePath);
            res.send(results);
        });
    },
    logError);

app.listen(8008, () => console.log('Example app listening on port 8008!'));

package.json

{
  "name": "code-coverage",
  "version": "0.0.1",
  "description": "code coverage results endpoint",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "boop",
  "license": "ISC",
  "dependencies": {
    "body-parser": "^1.17.2",
    "cors": "^2.8.4",
    "crypto": "0.0.3",
    "express": "^4.15.4",
    "extend": "^3.0.1",
    "fs-extra": "^4.0.1",
    "istanbul": "^0.4.5",
    "preflight": "^0.2.0"
  }
}