将 angular 6 升级到 9 的最佳方法是什么？

Question

Currently, my project is running in angular 6, I have to upgrade it in angular 9 now so what is the best way to upgrade? which is the main point to focus on when we upgrade it? Share your knowledge

Answer 1

This is the best doc you can follow as of today from angular:)

https://update.angular.io/#6.0:9.0

with a warning from angular

Warning: We do not recommend moving across multiple major versions.

You need to focus on these after conversion to make it work -

1. Rxjs version may change which may break your code
2. I don't remember HttpClient was present in angular 6, if not you should replace your import in app.module for Http calls
3. Update all your packages that should support angular 9
4. If you are using lazy loading the way it should be called in app.routing.ts changes now in angular 9 compared to angular 6

You can use this to update all your packages to the latest version

npm i -g npm-check-updates
ncu -u
npm install

Note: I may miss some points sorry for that. These are what I remember as of now:)

Answer 2

You should follow the official upgrade guide: https://update.angular.io/#6.0:9.0l3 .

There are quite a few steps involved as shown on that page. Chances are, you will run into issues as you perform the steps. Google or post separate questions for each issue as you encounter them. Good thing is, many of upgrade issues have been posted and solved, which should make it a little easier.

You might run into issues with dependency versions, and might stick to version 8 for the time being, until all of your dependencies are updated.

Good luck!