fusion-cli/build/convert-coverage.js

/** Copyright (c) 2018 Uber Technologies, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow
 */

/* eslint-env node */

const fs = require('fs');

// Jest writes coverage after the process exits
// so we need to poll and wait for all coverage files.
const waitForAllCoverage = dirs => {
  const maxTries = 10000;
  let numTries = 0;
  return Promise.all(
    dirs.map(
      dir =>
        new Promise((resolve, reject) => {
          const interval = setInterval(() => {
            const coverageExists = fs.existsSync(
              `${dir}/coverage/coverage-final.json`
            );
            numTries += 1;
            if (coverageExists) {
              clearInterval(interval);
              resolve();
            } else if (numTries > maxTries) {
              clearInterval(interval);
              reject();
            }
          }, 100);
        })
    )
  );
};

module.exports = function(rootDir /*: string */) {
  return waitForAllCoverage([rootDir]).then(() => {
    const createReporter = require('istanbul-api').createReporter;
    const istanbulCoverage = require('istanbul-lib-coverage');

    const map = istanbulCoverage.createCoverageMap();
    const reporter = createReporter();

    [rootDir].forEach(dir => {
      // $FlowFixMe
      const coverage = require(`${dir}/coverage/coverage-final.json`);
      Object.keys(coverage).forEach(filename => {
        const obj = coverage[filename];
        // It seems coverage objects are arbitrarily nested or not
        // See: https://github.com/fusionjs/fusion-cli/pull/489
        map.addFileCoverage(obj.data ? obj.data : obj);
      });
    });

    reporter.dir = `${rootDir}/coverage`;
    reporter.addAll(['json', 'lcov', 'text', 'cobertura']);
    reporter.write(map);
  });
};