Nativescript with Jade, SCSS and Babel

gulpfile.js

// modified from this: https://github.com/emiloberg/nativescript-emulator-reload

// all sources

var babelSrc = [ 'src/**/*.js', '!src/tns_modules', '!src/tns_modules/**', '!src/node_modules', '!src/node_modules/**' ];
var jadeSrc = [ 'src/**/*.jade' ];
var sassSrc = [ 'src/**/*.scss' ];
var resources = [ 'src/{App_Resources,tns_modules,node_modules}/**', 'src/package.json'];

// Which emulator to run?
//    iPhone-4s, iPhone-5, iPhone-5s, iPhone-6-Plus, iPhone-6,
//    iPad-2, iPad-Retina, iPad-Air, Resizable-iPhone, Resizable-iPa
var emulator = 'iPhone-5';

var gulp = require('gulp');
var spawn = require('child_process').spawn;
var babel = require('gulp-babel');
var jade = require('gulp-jade');
var sass = require('gulp-sass');
var rename = require('gulp-rename');
var mergeStream = require('merge-stream');
var del = require('del');

gulp.task('emulate', function(cb) {
  var child = spawn('tns', ['emulate', 'ios', '--device', emulator], {cwd: process.cwd()});
  var stdout = '';
  var stderr = '';

  child.stdout.setEncoding('utf8');
  child.stdout.on('data', function (data) {
    stdout += data;
    console.log(data);
  });

  child.stderr.setEncoding('utf8');
  child.stderr.on('data', function (data) {
    stderr += data;
    console.log(chalk.red(data));
  });

  child.on('close', function(code) {
    console.log('Done with exit code', code);
  });

  cb();

});


gulp.task('clean', function(cb) {
  del("app/**", cb);
});

function compileBabel(src) {
  return gulp.src(src)
  .pipe(babel({ stage: 1, blacklist: ["strict"]  }))
  .pipe(gulp.dest('app'));
}
function compileJade(src) {
  return gulp.src(src)
  .pipe(jade({pretty: true}))
  .pipe(rename({extname:".xml"}))
  .pipe(gulp.dest('app'));
}
function compileSass(src) {
  return gulp.src(src)
  .pipe(sass().on('error', sass.logError))
  .pipe(gulp.dest('app'));
}
function moveResources(src) {
  return gulp.src(src)
  .pipe(gulp.dest('app'));
}

gulp.task('compile', function() {
  return mergeStream(
    compileBabel(babelSrc),
    compileJade(jadeSrc),
    compileSass(sassSrc),
    moveResources(resources)
  );
});

gulp.task('watch', ['compile', 'emulate'], function(callback) {
  gulp.watch(babelSrc, function(e) { compileBabel(e.path); gulp.start('emulate');});
  gulp.watch(jadeSrc, function(e) { compileJade(e.path); gulp.start('emulate');});
  gulp.watch(sassSrc, function(e) { compileSass(e.path); gulp.start('emulate');});
  gulp.watch(resources, function(e) { moveResources(e.path); gulp.start('emulate');});
});


gulp.task('default', ['compile'], function() { });

If it is unclear, everything goes in the src directory instead of app.