How can I utilize Gulp.watch in Visual Studio 2015?

I want to apply a Gulp watcher to my LESS files so Gulp will create css files whenever a LESS file gets saved.

How can I do this? It doesn't seem to be correct/sufficient to write something like this:

var gulp = require("gulp");
var moreLess = require("gulp-more-less");
var concatCss = require("gulp-concat-css");

var lessInFolder = "./Less/**/*.less";

gulp.task("less", function ()
{
  gulp.src(lessInFolder).pipe(moreless()).pipe(concatCss()).pipe(gulp.dest("./css"));
});

gulp.watch(lessInFolder, ["less"]);

your help is appreciated.