gulpfile.js

const gulp = require('gulp');

const sass = require('gulp-sass');
const cssnano = require('gulp-cssnano');
const rev = require('gulp-rev');
const uglify = require('gulp-uglify-es').default;
const imagemin = require('gulp-imagemin');
const del = require('del');


gulp.task('css', function(done){
    console.log('css minifying');
    gulp.src('./assets/scss/**/*.scss')
    .pipe(sass())
    .pipe(cssnano())
    .pipe(gulp.dest('./assets/css'));
   
    gulp.src('./assets/**/*.css')
    .pipe(rev())
       .pipe(gulp.dest('./public/assets'))  // write rev'd assets to build dir
       .pipe(rev.manifest({
           base:'./public/assets',
           merge:true
       }))
       .pipe(gulp.dest('./public/assets'));
       done();
   
   })
   
   gulp.task('js', function(done){
       console.log('minifying js...');
        gulp.src('./assets/**/*.js')
       .pipe(uglify())
       .pipe(rev())
       .pipe(gulp.dest('./public/assets'))  // write rev'd assets to build dir
       .pipe(rev.manifest({
           base:'./public/assets',
           merge:true
       }))
       .pipe(gulp.dest('./public/assets'))
       done();
   });

   gulp.task('images', function(done){
    console.log('compressing images...');
    gulp.src('./assets/**/*.+(png|jpg|gif|svg|jpeg)')
    .pipe(imagemin())
    // .pipe(gulp.dest('./public/assets'))
    .pipe(rev())
        .pipe(gulp.dest('./public/assets'))  // write rev'd assets to build dir
        .pipe(rev.manifest({
            base:'./public/assets',
            merge:true
        }))
        .pipe(gulp.dest('./public/assets'));
        done();
});
   
   
   gulp.task('clean:assets', function(done){
       del.sync('./public');
       del.sync('./rev-manifest.json');
       //this will delete the manifest every time gulp build runs ,so may solve your problem of manifest adding,deleting,etc.
       done();
   });
   
   
   gulp.task('build', gulp.series('clean:assets' , 'images' , 'css' , 'js'), function(done){
       console.log('Building assets');
       done();
   });