Jest Coverage Helper for Gitlab

jest.config.json

{
  ...
  "reporters": ["default", "<rootDir>/test-helpers/simple-text-summary.js"],
  ...
}

simple-text-summary.js

#!/usr/bin/env node
const fs = require('fs');
const path = require('path');
const { parseString } = require('xml2js');

const coverageFile = path.join(__dirname, '../coverage/clover.xml')

const coverageReader = (err, { coverage }) => {
  if (err) {
    console.error('Could not process XML!\n');
    console.error(err.toString());
    return;
  }

  const {
    statements,
    coveredstatements,
    conditionals,
    coveredconditionals,
    methods,
    coveredmethods,
    elements,
    coveredelements
  } = coverage.project[0].metrics[0]['$'];

  const statementPercent = +coveredstatements / +statements;
  const conditionalPercent = +coveredconditionals / +conditionals;
  const methodPercent = +coveredmethods / +methods;
  const elementPercent = +coveredelements / +elements;

  const sum = statementPercent + conditionalPercent + methodPercent + elementPercent;

  // Total is (sum / 4) * 100 which translates to * 25
  console.log(`Total Coverage: ${(sum * 25).toFixed(2)}%`)
};

fs.readFile(coverageFile, 'utf8', async (err, data) => {
  if (err) {
    console.error('Could not process coverage results.');
    console.error('Make sure the "clover" reporter is enabled and the file has been written.\n');
    console.error(err.toString());
    return;
  }

  parseString(data, coverageReader);
});