angular-hybrid-demo
This is a demo project of lazy-loading both AngularJS AND Angular states with ui-router and bundling them with Webpack!
Under the hood this uses:
- Angular 4.x
- AngularJS ~1.5.x
- UI-Router
- Angular NgUpgrade 4.x
- ocLazyLoad
- Webpack 2.x
- TypeScript 2.x
Running
npm i
npm start
- Open browser to http://localhost:9999
Nitty-gritty
Structure
โโโ app
โย ย โโโ admin - ng2 component module
โย ย โย ย โโโ admin.component.ts - ng2 module for admin state
โย ย โย ย โโโ admin.module.ts - ng2 primary component for admin state
โย ย โย ย โโโ admin.state.ts - State definitions for admin state
โย ย โย ย โโโ reset - ng2 sub-state component
โย ย โย ย โโโ reset.component.ts - ng2 component
โย ย โ
โย ย โโโ common - ng1/ng2 common modules
โย ย โย ย โโโ common-ng1.module.js - ng1 common module (includes downgraded ng2)
โย ย โย ย โโโ common-ng2.module.ts - ng2 common module (includes upgraded ng1)
โย ย โย ย โโโ components
โย ย โย ย โย ย โโโ button.component.js - ng1 component
โย ย โย ย โย ย โโโ toggle.component.ts - ng2 component
โย ย โย ย โโโ services
โย ย โย ย โโโ admin.service.js - ng2 service
โย ย โย ย โโโ login.service.ts - ng1 service
โย ย โ
โย ย โโโ login - ng1 component module
โย ย โย ย โโโ hello - ng1 subview component
โย ย โย ย โย ย โโโ hello.controller.js - ng1 controller
โย ย โย ย โย ย โโโ hello.template.js - es6 template
โย ย โย ย โ
โย ย โย ย โโโ login.controller.js - ng1 controller
โย ย โย ย โโโ login.module.js - ng1 module
โย ย โย ย โโโ login.state.js - login states
โย ย โย ย โโโ login.template.js - es6 template
โ โ
โย ย โโโ app.module.js - ng1 main app module
โย ย โโโ app.state.js- state definitions for lazy-loading
โย ย โโโ upgrade.module.js - ng2 upgrade module
โ
โโโ utils
โย ย โโโ config-routing.js - Basic config for our ui-router
โย ย โโโ load-ng1-module.js - ocLazyLoad wrapper inside of ui-router transition callback
โ
โโโ adapter.js - angular upgrade adapter
โโโ bootstrap.js - bootstrap ng1 module via adapter
โโโ polyfills.js - corejs and such to be loaded by webpack
โโโ vendor.js - external libs that need to be loaded by webpack
How does this work?
Adapter Magic
In ./adapter.js
we create a new Angular2 UpgradeAdapter
. During this time we include
require in ./app/upgrade.module.js
which is the Angular2 master module that is
Angular uses under the hood to orchestrate the upgrade process.
If you have components/pipes/providers that need to be registered globally
UpgradeModule
is the module to do that in. In there you can see where I include
CommonNg2Module
which contains ng2 providers and components along with
upgraded ng1 services and directives.
You might also notice that in the adapter file, I also use require
to bring
in the UpgradeModule
after the adapter. You might also notice that in the
UpgradeAdapter
I also use forwardRef
in the function invocation. This is because
several other files need to include and use the adapter. For example, in ./app/common/common-ng2-module.js
we import the adapter so we can upgrade ng1 components. Without doing this, the module loader
tries to include UpgradeModule
which imports CommonNg2Module
which imports the adapter.
By including the UpgradeModule
after the adapter is created the modules load in order, however,
because classes aren't hoisted UpgradeModule
is not available. We can use the forwardRef
function
to accomplish this so that at runtime things are brought together at the right time.
Since we are upgrading ng1 components and services, we need a common module for ng1 that is registered at runtime without lazy-loading so that the adapter knows how to resolve those ng1 dependencies.
Its important to note due to the scoping of ng2, we also have to include CommonNg2Module
in all the state modules such as AdminModule
.
Router Magic
UI-Router has the ability for us to define what we call 'future states'. These are states that tell the router, 'hey i know about something here!' lets load it and then re-run state compilation which now includes the new state metadata.
Ok, thats cool but why not just declare them all in one place? Sometimes your states can get very comprehensive with resolves, substate definitions, etc. All that information would need to be loaded in the initial download causing the payload to increase. Also, all of that logic should live next to where its defined so having the comprehensive states in the module definition is ideal.
Lazy Loading Magic
Webpack allows us to do 'code splitting' which will statically analyze the code to find
System.import('some-file.js')
and at build time re-write this to reference some magical
bundle it made. Its important to note, this is static code analysis, so doing fancy code
that does this all black magic will not work since it actually changes your code to a new path.
If you use the system-js loader plugin, you can accomplish the later but for this demonstration
we do not do that.
Looking at ./app/app.state.js
we see I have some System.import
s wrapped in 2 different
functions. The first function (loadNg1Module
) is a Angular1 helper that calls ./utils/load-ng1-module.js
function
that when invoked will pass the resolve promise from the import to ocLazyLoad to recursively
resolve and register all our ng1 modules. loadChildren
in will lazy-load the Angular modules
for us.