At the end of the Gulpfile.js file we'll write down some tasks, including the default task, which runs a sequence of tasks of the build process. These tasks may look like the following:

gulp.task('set-development', development.task); 
gulp.task('set-production', production.task); 
gulp.task('test',['scss-lint','validate-html']); 
gulp.task('build', ['clean','copy','compile-js','compile-sass','compile-html']); 
gulp.task('default', ['set-development','server', 'watch']); 
gulp.task('deploy', ['set-production','server', 'watch']); 

The default task sets the environment to development by calling the set-development task first. Then it runs the server task, and starts the watch task after that. Because the server task depends on the build task, the build task always runs before the server task (Browsersync) starts. The deploys task does the same as the default task, but sets the environment to production in the...