bower-purge

utility to remove junk from bower_components folder optimized for Polymer components.
Only files needed are left as specified in bowerPurge.keep array. Use as a gulp task.

install

npm i bower-purge --save-dev

use

add configuration to your project bower.json file

"bowerPurge": {
    "deleteDir": ["/test/", "/demo/"],
    "keep": ["bower.json", ".html", ".js"]
}

where
deleteDir is a list of folders to be deleted (folder name inside forward slashes / for filepath.includes(dir))
keep is a list of file path endings to be kept (for filepath.endsWith(str))
NOTE:
DeleteDir runs first, so files matching keep will be deleted in these folders.
Do NOT use globs or wildcards.

use as gulp task

As a part of gulp build, copy bower.json to build folder and run bower install.
the 'bower-purge' task must run in the build folder after bower install completes.

const bowerPurge = require('bower-purge');
var buildFolder = 'your_build_folder';

gulp.task('bower-purge', function(cb){
    process.chdir(buildFolder);
    bowerPurge({dryRun:false, quiet:true}, cb);
});

advanced gulp example

install dependencies and cleanup after, in one gulp task

const bowerPurge = require('bower-purge');
const install = require('gulp-install');
const stripComments = require('gulp-strip-comments');
const htmlmin = require('gulp-htmlmin'); // can not minify JS ES6 because it uses uglifyJS
const pump = require('pump'); 

dest = 'your_build_folder';

gulp.task('bower-install-and-purge', function(cb){

    // callback heaven! hell for C!# (read: see-blunt) programmers! 
    // promises are for politicians not to keep
    step1(function(){
        step2(function(){
            step3(cb);
        });
    });

    /** 1. run npm install */
    function step1(_cb){
        pump([
            gulp.src([`${dest}bower.json`]), 
            install({args: ['--production' ]}),
            gulp.dest(dest)
        ], _cb);
    }

    /** 2. purge bower_components folder */
    function step2(_cb){
        process.chdir(dest);
        bowerPurge({dryRun:false, quiet:true}, _cb);
    }

    /** 3. minify html */
    function step3(_cb){
        pump([
            gulp.src([`${dest}bower_components/**/*.html`], {base: dest }), 
            htmlmin({collapseWhitespace: true, removeComments: true}),
            gulp.dest(dest)
        ], _cb);
    }
});

dryRun

before use, make a dry run to see what files will be deleted without actulally deleting them:

bower-purge --dryRun

if you delete needed files, no worries, run bower install to restore them. (if bower install does do nothing, delete bower_components folder and run bower install again.)

in Windows CLI terminal, you can run run.cmd see this file for CLI usage.

similar utility for node_modules

try npm node-modules-prod or github alfalabs/node-modules-prod

credits

based on https://github.com/mkramb/bower-clean