Webpack2 Angular2 ng-bootstrap Tree Shaking

问题

I'm currently using https://github.com/ng-bootstrap/ng-bootstrap in my angular2 application and use webpack2 to build all ts files.

i'm only using Modal Component from NgbModule for now, but in minified file i can still see NbgAccordian and other modules reference which is not used in my app

@ng-bootstrap/ng-bootstrap": "^1.0.0-alpha.15

i tried import { NgbModule, NgbModal, NgbModalOptions, ModalDismissReasons, NgbActiveModal } from '@ng-bootstrap/ng-bootstrap'; but didn't worked as expected also. Is this something to do with tree shaking or the way Ngbmodule is written. Any options to omit unused modules from vendor.js file

vendor.ts

// Angular

import '@angular/core';
import '@angular/common';
import '@angular/forms';
import '@angular/http';
import '@angular/platform-browser';
import '@angular/platform-browser-dynamic';
import '@angular/router';


// RxJS
import 'rxjs';
// Other vendors for example jQuery, Lodash or Bootstrap
// You can import js, ts, css, sass, ...

import  '@ng-bootstrap/ng-bootstrap';
import  'moment/moment';
import  'angular2-toaster/angular2-toaster';
import  'angular2-moment';
import  'ng2-tag-input';

import 'ng2-img-cropper';

webpack.prod.js

var webpack = require('webpack');
var webpackMerge = require('webpack-merge');
var ExtractTextPlugin = require('extract-text-webpack-plugin');
var commonConfig = require('./webpack.common.js');
var CompressionPlugin = require("compression-webpack-plugin");
var helpers = require('./helpers');

var packageJson = require('../../package.json');
var version = packageJson.version;
const ENV = process.env.NODE_ENV = process.env.ENV = 'production';
var drop_console = true;

//https://github.com/mishoo/UglifyJS2#mangle
//https://github.com/mishoo/UglifyJS2#compressor-options
https://github.com/mishoo/UglifyJS2
module.exports = webpackMerge(commonConfig, {
    devtool: "source-map",
    plugins: [
        new webpack.LoaderOptionsPlugin({

            minimize: true,
            debug: false,
            options: {

                /**
                 * Html loader advanced options
                 *
                 * See: https://github.com/webpack/html-loader#advanced-options
                 */
                // TODO: Need to workaround Angular 2's html syntax => #id [bind] (event) *ngFor
                htmlLoader: {
                    minimize: true,
                    removeAttributeQuotes: false,
                    caseSensitive: true,
                    customAttrSurround: [
                        [/#/, /(?:)/],
                        [/\*/, /(?:)/],
                        [/\[?\(?/, /(?:)/]
                    ],
                    customAttrAssign: [/\)?\]?=/]
                }

            }
        }),
        new webpack.NoErrorsPlugin(),
        new webpack.optimize.UglifyJsPlugin({ // https://github.com/angular/angular/issues/10618
            minimize: true,
            sourceMap: true,

             // Don't beautify output (enable for neater output)
            beautify: false,

            // Eliminate comments
            comments: false,



            mangle:  {
                toplevel : true,
                screw_ie8: true,
                keep_fnames: false
            },
            compress: {
                screw_ie8: true,

                dead_code : true,

                unused : true,

                warnings: false,

                // Drop `console` statements
                 drop_console: drop_console
            }

        }),
        new CompressionPlugin({
            regExp: /\.css$|\.html$|\.js$|\.woff$|\.map$/,
            algorithm: "gzip",
            threshold: 2 * 1024,
            minRatio: 0.8
        }),
        new webpack.DefinePlugin({
            'process.env': {
                'ENV': JSON.stringify(ENV)
            }
        })
    ]
});

----------------------------- Updates on 04/20/2017 ---------------------

Had to update my modules, and component files to import deeplink reference of files instead of root to exclude unused modules from ng bootstrap

app.modules.ts

import {  NgbModalModule }                            from '@ng-bootstrap/ng-bootstrap/modal/modal.module';
import {  NgbTooltipModule}                            from '@ng-bootstrap/ng-bootstrap/tooltip/tooltip.module';
import {  NgbAlertModule }                            from '@ng-bootstrap/ng-bootstrap/alert/alert.module';

app.component.ts

import {NgbModal, NgbModalOptions} from '@ng-bootstrap/ng-bootstrap/modal/modal';
import { ModalDismissReasons }                  from '@ng-bootstrap/ng-bootstrap/modal/modal-dismiss-reasons';
import { NgbActiveModal} from '@ng-bootstrap/ng-bootstrap/modal/modal-ref';
import { NgbTooltipConfig }                        from "@ng-bootstrap/ng-bootstrap/tooltip/tooltip-config";

vendor.ts

import { NgbModalModule, NgbModal, NgbModalOptions, ModalDismissReasons, NgbActiveModal, NgbTooltipModule, NgbTooltipConfig, NgbAlertModule } from '@ng-bootstrap/ng-bootstrap';

------ Further Updates ------------

Followed tree shaking configuration from

https://github.com/Andrey-Pavlov/angular2-webpack-starter/blob/d0a225851e6d63b03a21ad6b7a71552a941229ef/config/webpack.common.js#L220

回答1:

tl;dr; is that you can pick and choose only components that you use from ng-bootstrap but you need to import only what you are using.

If you are just using individual module(s) from the ng-bootstrap project than you should just import the modules used (instead of the whole NgbModule as you do today). Here is how (using modal as an example):

import {NgbModalModule} from '@ng-bootstrap/ng-bootstrap';

...

@NgModule({
  declarations: [AppComponent, ...],
  imports: [NgbModalModule.forRoot(), ...],
  bootstrap: [AppComponent]
})
export class AppModule {
}

Finally here is a live example in plunker: http://plnkr.co/edit/3TdcMzPBXb3OKWYIQisG?p=preview

Also, when using WebPack make sure that you import only what it used in your vendor.ts file (as import '@ng-bootstrap/ng-bootstrap'; will bring all the components);

回答2:

Even though I was following @pkozlowski.opensource recommendation, I was still seeing an ng-template error in the Accordion module. I ended up importing from a nested path, as I would do with rxjs/Observable:

import {NgbModalModule} from '@ng-bootstrap/ng-bootstrap/modal/modal.module';

...

@NgModule({
  declarations: [AppComponent, ...],
  imports: [NgbModalModule.forRoot(), ...],
  bootstrap: [AppComponent]
})
export class AppModule {
}

Hope that helps!

来源：https://stackoverflow.com/questions/43429897/webpack2-angular2-ng-bootstrap-tree-shaking