The new version, v10, of Angular has been published only hours ago and announced by this blog post. Although it may not appear as impactful as v9 (with Ivy and all), this release displays Angular team's commitment to keep Angular up-to-date and relevant. We found this very exciting and the timing was just right, because we are about to release ABP v3.0!
So, we jumped into the details of what changed and how to migrate. Here is what we found.
Major Changes
TypeScript v3.9 Support [breaking change]
Angular 9 was released with TypeScript 3.7 support. Soon TypeScript 3.8 was released and Angular v9.1 supported it. Not long after, another TypeScript version, 3.9, is released and Angular responds with v10, keeping up, not only with TypeScript, but also with TSLib and TSLint.
That is great news. Angular stays up-to-date. First of all, TypeScript 3.9 has performance improvements, which means faster Angular builds, especially in larger projects. Second, all latest TypeScript fixes and features are available to Angular developers. Last, but not the least, Angular developers will be using a more elaborate TypeScript configuration.
Earlier versions of TypeScript are no longer supported, so you have to install v3.9 in your project. I believe a major reason behind this is the next feature I will describe.
"Solution Style” tsconfig.json Files
"Solution Style” tsconfig.json file support was introduced by TypeScript v3.9 to overcome issues with cases where a tsconfig.json existed just to reference other tsconfig.json files, known as a "solution". Angular 10 makes use of that concept and improves IDE support and, consequently, developer experience.
A new file called tsconfig.base.json is introduced and what was inside the root tsconfig.json before is
