elm-coverage.js

gulp.task('elm:coverage', function () {
    var coverageHtml = new jsdom.JSDOM(fs.readFileSync(PATH_COVERAGE + 'coverage.html').toString()),
        mainOverview = coverageHtml.window.document.getElementsByClassName('overview')[0],
        mainOverviewBodyRows = Array.from(mainOverview.querySelectorAll('tbody tr'));

    var errors = mainOverviewBodyRows.reduce(function (accumulator, row) {
        var result = Array.from(row.querySelectorAll('td')).reduce(function (accumulator, cell) {
            var progress = cell.querySelector('progress');

            if (progress) {
                var value = progress.getAttribute('value'),
                    max = progress.getAttribute('max');

                if (value !== max) {
                    accumulator.hasErrors = true;
                    accumulator.values.push(value / max * 100 + '%');
                }
            } else {
                accumulator.values.push('n/a');
            }

            return accumulator;
        }, { hasErrors: false, values: [] });

        if (result.hasErrors) {
            var moduleName = row.querySelector('th code').innerHTML;

            result.values.unshift(moduleName);
            accumulator.push(result.values);
        }

        return accumulator;
    }, []);

    if (errors.length) {
        var firstRow = ['Module', 'case branches', 'Declarations', 'if/else branches', 'Lambdas', 'let declarations'];

        console.log('\n**** Modules below are required to have 100% coverage ****\n');
        console.log(table.table([firstRow].concat(errors)));

        throw 'Modules above are required to have 100% coverage';
    }
});