Implement Critical Path for CSS

[JeremieLitzler]

NPM package: npm install critical --save-dev

In the gulp file:

var critical = require('critical');

gulp.task('critical', ['build'], function (cb) {
    critical.generate({
        inline: true,
        base: 'dist/',
        src: 'index.html',
        dest: 'dist/index-critical.html',
        minify: true,
        width: 320,
        height: 480
    });
});

Source 1
Source 2a and Source 2b