Gulp Receipe: Rebuild only files that change

onlyChangedFilesGulp.js

// With gulp-watch:

var gulp = require('gulp');
var sass = require('gulp-sass');
var watch = require('gulp-watch');

gulp.task('default', function() {
  return gulp.src('sass/*.scss')
    .pipe(watch())
    .pipe(sass())
    .pipe(gulp.dest('dist'));
});