Why doesn't gulp.watch complete?

Question

css

I start the watch , it starts working but does not end (

Gulpfile:

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

gulp.task('sass', function() {
  return gulp.src('www/scss/**/*.scss')
  .pipe(sass())
  .pipe(gulp.dest('css'))
});


gulp.task('watch', function() {
    gulp.watch('www/scss/**/*.scss', gulp.parallel('sass'));
});

package.json:

{
  "name": "www",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "gulp": "^4.0.2",
    "gulp-rename": "^2.0.0",
    "gulp-sass": "^4.1.0",
    "gulp-watch": "^5.0.1"
  }
}

Answer 1

This is the focus. Watch tasks do not end, they execute the tasks listed in the second argument when changing watch files.