Node ES6 istanbul, isparta, mocha-co gulpfile example

gulpfile.js

'use strict';
var gulp = require('gulp');
var del = require('del');
var mocha = require('gulp-mocha-co');
var istanbul = require('gulp-istanbul');
var isparta = require('isparta');
var coverageEnforcer = require('gulp-istanbul-enforcer');

var paths = {
    server: {
        scripts:  ['server/src/**/*.js'],
        tests:    ['server/test/**/*.spec.js'],
        coverage: 'coverage/server'
    }
};

gulp.task('clean-coverage', function(cb) {
    return del(['coverage'], cb);
});

gulp.task('test-coverage-server', ['clean-coverage'], function(cb) {
    var coverageDir = paths.server.coverage;
    gulp.src(paths.server.scripts)
        .pipe(istanbul({ // Covering files
            instrumenter: isparta.Instrumenter,
            includeUntested: true
        }))
        .pipe(istanbul.hookRequire()) // Force `require` to return covered files
        .on('finish', function() {
            gulp.src(paths.server.tests, {read: false})
                .pipe(mocha({reporter: 'spec'}))
                .pipe(istanbul.writeReports({
                    dir: coverageDir,
                    reportOpts: {dir: coverageDir},
                    reporters: ['text', 'text-summary', 'json', 'html']
                }))
                .pipe(coverageEnforcer({
                    thresholds: {
                        statements: 80,
                        branches: 50,
                        lines: 80,
                        functions: 50
                    },
                    coverageDirectory: coverageDir,
                    rootDirectory : ''
                }))
                .on('end', cb);
        });
});