Gulp watch executes only one time - sass

Question

I know there are many questions with new gulp version . I had to change my gulpfile.js and now when I run it , it only executes once . I tried using return on gulp.watch function but it does nothing .
Here is my code :
'use strict';
var gulp = require('gulp');
var sass = require('gulp-sass');
var runSequence = require('run-sequence');
var iconfont = require('gulp-iconfont');
var async = require('async');
var consolidate = require('gulp-consolidate');
var sassLint = require('gulp-sass-lint');
gulp.task('sass', function(){
return gulp.src('app/scss/**/*.scss')
.pipe(sass())
.pipe(gulp.dest('app/css'))
});
gulp.task('sass-lint', function () {
return gulp.src('app/scss/**/*.s+(a|c)ss')
.pipe(sassLint())
.pipe(sassLint.format())
.pipe(sassLint.failOnError())
});
gulp.task('watch', gulp.series('sass'), function (){
gulp.watch('app/scss/**/*.scss', gulp.series(gulp.parallel('sass' , 'sass-lint' )));
});
gulp.task('build', function (callback) {
runSequence(['sass'],
callback
)
});
gulp.task('iconfont', function(done){
var iconStream = gulp.src(['app/images/svg/*.svg'])
.pipe(iconfont({
fontName: 'icons',
}));
async.parallel([
function handleGlyphs(cb) {
iconStream.on('glyphs', function(glyphs, options) {
gulp.src('conf/_iconfont-template.scss')
.pipe(consolidate('lodash', {
glyphs: glyphs,
fontName: 'icons',
fontPath: '../fonts/',
className: 's'
}))
.pipe(gulp.dest('app/scss/utilities/'))
.on('finish', cb);
});
},
function handleFonts (cb) {
iconStream
.pipe(gulp.dest('app/fonts/'))
.on('finish', cb);
}
], done);
});
Here is what i get in a terminal :

Answer 1

Your problem is mainly here:
// your version
gulp.task('watch', gulp.series('sass'), function (){
// should be:
gulp.task('watch', gulp.series('sass', function (done) {
gulp.task now takes only two arguments.
Other comments:
This part of your 'watch' task is strange:
gulp.series(gulp.parallel('sass' , 'sass-lint' )));
gulp.series is doing nothing there, presumably you want :
gulp.parallel('sass' , 'sass-lint' ));
Final 'watch' task with done callback to signal async completion.
gulp.task('watch', gulp.series('sass', function (done){
gulp.watch('app/scss/**/*.scss', gulp.parallel('sass' , 'sass-lint'));
done();
}));
You don't need the run-sequence plugin anymore. You could change the 'build' task to use gulp.series instead.