Skip to main content

Angular 6–Dependency Injection changes

One of the smaller changes that the Angular team introduced with the Angular 6 release is the support for tree-Shakable providers.

From the documentation:

Tree shaking is the ability to remove code that is not referenced in an application from the final bundle. Tree-shakable providers give Angular the ability to remove services that are not used in your application from the final output. This significantly reduces the size of your bundles.

To enable this scenario, you have to change your code and move from modules referencing services to services referencing modules.

Until now we always provided a service by registering it as part of our ngModule providers:

The problem with the code above is that the Angular compiler cannot identify at build time if this service will be required or not. Because it's always possible to inject a service directly using injector.get(Service), Angular cannot identify all of the places in your code where this injection could happen. Thus, services provided in modules are not tree-shakeable.

To make our service tree-shakeable, the information about how to construct an instance of the service (the provider definition) needs to be a part of the service class itself.

Remark: If necessary you can further configure the service using a factory function on the injector.

Popular posts from this blog

DevToys–A swiss army knife for developers

As a developer there are a lot of small tasks you need to do as part of your coding, debugging and testing activities.  DevToys is an offline windows app that tries to help you with these tasks. Instead of using different websites you get a fully offline experience offering help for a large list of tasks. Many tools are available. Here is the current list: Converters JSON <> YAML Timestamp Number Base Cron Parser Encoders / Decoders HTML URL Base64 Text & Image GZip JWT Decoder Formatters JSON SQL XML Generators Hash (MD5, SHA1, SHA256, SHA512) UUID 1 and 4 Lorem Ipsum Checksum Text Escape / Unescape Inspector & Case Converter Regex Tester Text Comparer XML Validator Markdown Preview Graphic Color B

Help! I accidently enabled HSTS–on localhost

I ran into an issue after accidently enabling HSTS for a website on localhost. This was not an issue for the original website that was running in IIS and had a certificate configured. But when I tried to run an Angular app a little bit later on http://localhost:4200 the browser redirected me immediately to https://localhost . Whoops! That was not what I wanted in this case. To fix it, you need to go the network settings of your browser, there are available at: chrome://net-internals/#hsts edge://net-internals/#hsts brave://net-internals/#hsts Enter ‘localhost’ in the domain textbox under the Delete domain security policies section and hit Delete . That should do the trick…

Azure DevOps/ GitHub emoji

I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.