Skip to main content

Upgrading Angular 2 from beta 17 to RC4–Lessons learned Part 1

Last week I had to make a change to an existing Angular 2 codebase(written using Angular 2 Beta 17). Before applying the change I decided to (quickly) update the code to Angular 2 RC4. Turns out that quickly wasn’t so quick after all… A lot of things have changed between the beta and RC.

Here are some of the lessons I learned along the way:

NPM packages

The NPM packages have been renamed and do no longer contain Angular2 in their name. Instead they switched to @angular.

Here is my updated package.json:

Of course I had to update the imports inside my components as well:

import {Component} from "@angular/core";
import {ROUTER_DIRECTIVES} from '@angular/router'
import {HTTP_PROVIDERS}    from '@angular/http';

System.config changes

After updating my NPM references, I got another error:

Error: SyntaxError: Unexpected token <(…)

Angular was no longer able to load my scripts. When I took a look at the network tab in the browser I noticed that the wrong URL was used. I had to update my system.config to fix this:

 

https://www.towfeek.se/2016/05/upgrading-to-angular-2-rc1-from-beta-lessons-learned/

https://angular.io/docs/ts/latest/guide/router.html

New script references

Now that the NPM packages were imported correctly, I had good hope that everything would work. But no, a new error appeared:

Reflect.getOwnMetadata is not a function

Some new scripts had to be referenced that were not required before. So I updated my script references and added the following:

We finally started to make some progress, next issue is tackling the new router. But that is for another blog post.

Labels:

Popular posts from this blog

Podman– Command execution failed with exit code 125

After updating WSL on one of the developer machines, Podman failed to work. When we took a look through Podman Desktop, we noticed that Podman had stopped running and returned the following error message: Error: Command execution failed with exit code 125 Here are the steps we tried to fix the issue: We started by running podman info to get some extra details on what could be wrong: >podman info OS: windows/amd64 provider: wsl version: 5.3.1 Cannot connect to Podman. Please verify your connection to the Linux system using `podman system connection list`, or try `podman machine init` and `podman machine start` to manage a new Linux VM Error: unable to connect to Podman socket: failed to connect: dial tcp 127.0.0.1:2655: connectex: No connection could be made because the target machine actively refused it. That makes sense as the podman VM was not running. Let’s check the VM: >podman machine list NAME         ...
Read more

Cache stampede: when our cache turned against us

While investigating some performance issues, we ran into an ASP.NET Core API that cached a fairly expensive aggregation query for 60 seconds. Under normal load, that was fine: one request rebuilds the cache, everyone else reads from it. Under peak load, dozens of requests would arrive in that same expiry window, all see a cache miss, and all fire the same expensive query in parallel. The database didn't like that. That was the moment when our caching layer stopped helping and started hurting. A burst of requests comes in at the same time, all miss the cache, and all go hammer the database or the downstream API at once. That's a cache stampede . The cache was supposed to protect our backend, and for a few hundred milliseconds it did the opposite. Why this happens IMemoryCache.GetOrCreate (and its async sibling) looks like it protects you, but it doesn't add any locking on its own. Look at the naive version: public async Task<Report> GetReportAsync(string key) ...
Read more

VS Code Planning mode

After the introduction of Plan mode in Visual Studio , it now also found its way into VS Code. Planning mode, or as I like to call it 'Hannibal mode', extends GitHub Copilot's Agent Mode capabilities to handle larger, multi-step coding tasks with a structured approach. Instead of jumping straight into code generation, Planning mode creates a detailed execution plan. If you want more details, have a look at my previous post . Putting plan mode into action VS Code takes a different approach compared to Visual Studio when using plan mode. Instead of a configuration setting that you can activate but have limited control over, planning is available as a separate chat mode/agent: I like this approach better than how Visual Studio does it as you have explicit control when plan mode is activated. Instead of immediately diving into execution, the plan agent creates a plan and asks some follow up questions: You can further edit the plan by clicking on ‘Open in Editor’: ...
Read more