Forward reference tasks not defined before use

Question

I am using multiple files with gulp@4 where the main gulpfile.js includes all other files within the ./tasks/ directory. We are using the npm gulp-hub package to include multiple gulpfiles with the ./tasks/ directory. However we are getting the following error message when calling the tasks.

Forward referenced tasks 'clean-minify-js` not defined before use

How can we include multiple gulpfiles within the main gulpfile.js so that we can call tasks?

Current gulpfile.js:

'use strict';

var gulp = require('gulp'),
    HubRegistry = require('gulp-hub');
    
var genericHub = new HubRegistry('./tasks/scripts.js');
gulp.registry(genericHub);

var watchers = function(done) {
  gulp.watch('src/*.js', gulp.parallel('clean-minify-js'));
  done();
}

gulp.task('watch', gulp.series(watchers));

Current ./tasks/scripts.js

'use strict';

var gulp = require('gulp'),
    clean = require('gulp-clean'),
    uglify = require('gulp-uglify');
    
gulp.task('clean-scripts', function() {
  return gulp.src(dest.js)
             .pipe(clean({read:false, force: true});
});

gulp.task('minify-js', gulp.series('clean-scripts', function() {
   gulp.src(src.js)
       .pipe(uglify())
       .pipe(gulp.dest(dest.js));
}));

gulp.task('clean-minify-js', gulp.series('minify-js'));

Folder structure:

• some/path/gulpfile.js
• some/path/tasks/scripts.js

Answer 1

To resolve the issue, I had to do the following.

• Use the require-dir package to include all files within the ./tasks/ directory.
• convert tasks that were designed for gulp@3.9.1 into functions for gulp@4
• use gulp.series to set the functions to run in the particular order we needed

gulpfile.js

'use strict';

var gulp = require('gulp'),
    requireDir = require('require-dir');
requireDir('./tasks/');    

var watchers = function(done) {
  gulp.watch('src/*.js', gulp.parallel('clean-minify-js'));
  done();
}

gulp.task('watch', gulp.series(watchers));

./tasks/scripts.js

'use strict';

var gulp = require('gulp'),
    clean = require('gulp-clean'),
    uglify = require('gulp-uglify');

function cleanScripts() {
  return gulp.src(dest.js)
             .pipe(clean({read:false, force: true});
}

function minJs() {
  return gulp.src(src.js)
       .pipe(uglify())
       .pipe(gulp.dest(dest.js));
}

gulp.task('clean-minify-js', gulp.series(cleanScripts, minJs));