27/07/2017
Why Angular 4?? Why even Angular 3?? What is going on?
Angular uses SEMVER
Back in September when the new Angular was finally released, the Angular team also announced they will switch to Semantic Versioning (SEMVER).
As the name already explains, Semantic Versioning is all about adding meaning to version numbers. This allows developers to not only reason about any upgrade we do, but we can even let tools such as NPM do it in a automatic and safe manner for us.
A semantic version consists of three numbers:
2.3.1 - major = breaking change, minor = new features, not breaking, patch = bugfixes, not breaking
Whenever you fix a bug and release it, you increase the last number, if a new feature is added, you increase the second number and whenever you release a breaking change you increase the first number.
“A breaking change happens whenever you as a developer and consumer of a library, have to step in and adjust your code after a version upgrade.”
So what does this mean for the Angular team? As with every evolving piece of software, breaking changes will occur at some point. For example, giving a compiler error for existing application bugs that went unnoticed with the previous compiler version, anything, that will break an existing application when upgrading Angular, requires the team to bump the major version number.
Just to be clear, as also Igor mentioned in his talk. Right now, even just upgrading Angular’s TypeScript dependency from v1.8 to v2.1 or v2.2 and compile Angular with it, would technically cause a breaking change. So they’re taking SEMVER very, very seriously.
Breaking changes don’t have to be painful!
People that have been following the Angular community for a while, definitely know what I’m talking about. We went from Angular 1 to Angular 2, and it was a total breaking change, with new APIs, new patterns. That was obvious: ultimately Angular 2 was a complete rewrite. (Even though there are upgrade options for you available)
Changing from version 2 to version 4, 5, … won’t be like changing from Angular 1. It won’t be a complete rewrite, it will simply be a change in some core libraries that demand a major SEMVER version change. Also, there will be proper deprecation phases to allow developers to adjust their code.
Internally at Google, the Angular team uses a tool for handling automatic upgrades, even of breaking changes. This is still something that has to be planned in more detail, but the team is working hard on making this tool generally available, most probably in 2017 in time for version 5.
It’s just “Angular”
As you might have already guessed, the term “Angular 2” is also kind of deprecated once we get to version 4, 5 etc. That said, we should start naming it simply “Angular” without the version suffix.
“It’s just ”
Also, we should start avoiding GitHub/NPM libraries prefixed with ng2- or angular2-.
