Why is Gulp running the same task twice? - gulp

Question

I am having a similar issue as the question posted here but none of the answers given there apply to my situation.
When I run the one and only task defined in my Gulpfile.js file it is getting executed twice.
I am using Gulp version 4.0.2
This is the contents of my Gulpfile.js file:
const { src, dest, watch, series, parallel } = require('gulp');
const sass = require('gulp-sass');
const rename = require('gulp-rename');
const postcss = require('gulp-postcss');
const autoprefixer = require('autoprefixer');
const cssnano = require('cssnano');
const files = {
bootstrapSrcPath: 'bootstrap-sass/bootstrap.scss',
bootstrapDstPath: 'Test'
};
exports.scssTask = series(
scssTaskFunc
);
function scssTaskFunc() {
return src(files.bootstrapSrcPath)
.pipe(sass({ style: 'expanded' }))
.pipe(dest(files.bootstrapDstPath))
.pipe(postcss([autoprefixer(), cssnano()]))
.pipe(rename({ suffix: '.min' }))
.pipe(dest(files.bootstrapDstPath));
}
This is the command I am running in the CMD prompt and the results:
C:\Users\myUser\source\repos\myProject> cmd.exe / c gulp - b "C:\Users\myUser\source\repos\myProject" --color--gulpfile "C:\Users\myUser\source\repos\myProject\Gulpfile.js" scssTask
[16: 10: 15]Using gulpfile ~\source\repos\myProject\Gulpfile.js
[16: 10: 15]Starting 'scssTask'...
[16: 10: 15] Starting 'scssTaskFunc'...
[16: 10: 17] Finished 'scssTaskFunc' after 1.7 s
[16: 10: 17]Finished 'scssTask' after 1.71 s
Process terminated with code 0.
It works and the output file is what I expect but it seems like a waste to do it twice.
This is the what gulp shows for tasks:
C:\Users\myUser\source\repos\myProject> gulp--tasks
[15: 57: 29]Tasks for ~\source\repos\myProject\Gulpfile.js
[15: 57: 29]└─┬ scssTask
[15: 57: 29]└─┬ <series>
[15:57:29] └── scssTaskFunc
Why is it running the task twice, once as the 'scssTask' and the second as the 'scssTaskFunc'?
Btw, this is my first attempt at gulp so I apologize if this is a derp question.

Answer 1

Your task isn't running twice, it just seems like it does because you're using gulp.series.
gulp.series and gulp.parallel are normally used to combine and compose tasks into larger operations. If, for example, you'd have a jsTaskFunc as well, you could create a task build like so:
exports.build = parallel(scssTaskFunc, jsTaskFunc);
and running gulp build would log something like this in your terminal:
[09:42:12] Starting 'build'...
[09:42:12] Starting 'scssTaskFunc'...
[09:42:12] Starting 'jsTaskFunc'...
[09:42:12] Finished 'scssTaskFunc' after 93 ms
[09:42:12] Finished 'jsTaskFunc' after 94 ms
[09:42:12] Finished 'build' after 111 ms
Something similar is happening now due to your use of gulp.series, because scssTask runs scssTaskFunc as a dependent task, but scssTask and scssTaskFunc are strictly speaking not the same task. Nothing gets run twice.
To avoid confusion, and because gulp.series isn't necessary, simply do:
exports.scssTask = scssTaskFunc;