You might get confused and may ask “is this a hoax? Isn’t it way too early seeing as Angular 2 has just been released late last year? What about Angular 3??”.
The answer is the following, First, forget that there is Angular 3, the reason is that Google jumped already so that the upgrades will be correlated to version 4. Second, is that there are only few revisions and features added in Angular 4 but as for syntax and logical flow of the framework, it should almost be the same with the version 2.
Next, let us have an overview of the new features of Angular 4. Here are the following new stuff in version 4 according to http://angularjs.blogspot.com;
“Our template binding syntax now supports a couple helpful changes. You can now use an if/else style syntax, and assign local variables such as when unrolling an observable.”
Universal, the project that allows developers to run Angular on a server, is now up to date with Angular again, and this is the first release since Universal, originally a community-driven project, which was adopted by the Angular team. This release now includes the results of the internal and external work from the Universal team over the last few months. The majority of the Universal code is now located in @angular/platform-server.
TypeScript 2.1 and 2.2 compatibility
We’ve updated Angular to a more recent version of TypeScript. This will improve the speed of ngc and you will get better type checking throughout your application.
Source Maps for Templates
Now when there is an error caused by something in one of your templates, we generate source maps that give a meaningful context in terms of the original template.
Flat ES Modules (Flat ESM / FESM)
We now ship flattened versions of our modules “rolled up” version of our code in the EcmaScript Module format. This format should help tree-shaking, help reduce the size of your generated bundles, and speed up build, transpilation, and loading in the browser in certain scenarios.
Experimental ES2015 Builds
We now also ship our packages in the ES2015 Flat ESM format. This option is experimental and opt-in. Developers have reported up to 7% bundle size savings when combining these packages with Rollup.
Experimental Closure Compatibility
All of our code now has Closure annotations, making it possible to take advantage of advanced Closure optimizations, resulting in smaller bundle sizes and better tree shaking.
There are a lot of improvements and is also easy when it pertains to switching or upgrading from Angular 2 to Angular 4. As of now, Angular 4 is so far stable and the version 5 is coming this year around October so better be knowledgeable in this framework as fast as you can!