Delete files and folders

You might want to delete some files before running your build. Since deleting files doesn't work on the file contents, there's no reason to use a gulp plugin. An excellent opportunity to use a vanilla node module.

Let's use the del module for this example as it supports multiple files and globbing:

$ npm install --save-dev gulp del

Imagine the following file structure:

.
├── dist
│   ├── report.csv
│   ├── desktop
│   └── mobile
│       ├── app.js
│       ├── deploy.json
│       └── index.html
└── src

In the gulpfile we want to clean out the contents of the mobile folder before running our build:

var gulp = require('gulp');
var del = require('del');

gulp.task('clean:mobile', function () {
  return del([
    'dist/report.csv',
    // here we use a globbing pattern to match everything inside the `mobile` folder
    'dist/mobile/**/*',
    // we don't want to clean this file though so we negate the pattern
    '!dist/mobile/deploy.json'
  ]);
});

gulp.task('default', ['clean:mobile']);

Delete files in a pipeline

You might want to delete some files after processing them in a pipeline.

We'll use vinyl-paths to easily get the file path of files in the stream and pass it to the del method.

$ npm install --save-dev gulp del vinyl-paths

Imagine the following file structure:

.
├── tmp
│   ├── rainbow.js
│   └── unicorn.js
└── dist

var gulp = require('gulp');
var stripDebug = require('gulp-strip-debug'); // only as an example
var del = require('del');
var vinylPaths = require('vinyl-paths');

gulp.task('clean:tmp', function () {
  return gulp.src('tmp/*')
    .pipe(vinylPaths(del))
    .pipe(stripDebug())
    .pipe(gulp.dest('dist'));
});

gulp.task('default', ['clean:tmp']);

This will only delete the tmp dir.

Only do this if you're already using other plugins in the pipeline, otherwise just use the module directly as gulp.src is costly.