Kendo-angular: ng add <package> always registers a theme

[tsvetomir]

I'm submitting a...

• Bug report

Current behavior

Executing ng add @progress/kendo-angular-* will always register a theme in angular.json. This would normally be "kendo-theme-default" unless the styles section already contains a known theme.

In any case, the theme must be manually removed from angular.json if it is not desired - e.g. a custom theme is in use.

Expected behavior

The schematic should register the styles only if there is no kendo-theme-* _package_ installed.

Minimal reproduction of the problem with instructions

1. Run ng new test-project --style=scss
2. Run cd test-project
3. Run ng add @progress/kendo-angular-buttons

4. Remove the object containing "kendo-theme-default" from styles in angular.json (two in total):

   {
       "input": "node_modules/@progress/kendo-theme-default/scss/all.scss"
   },
   

5. Add the following lines to src/styles.css:

   @import "~@progress/kendo-theme-default/scss/all";
   

6. Run ng add @progress/kendo-angular-inputs
7. Observe that angular.json now contains a reference to "kendo-theme-default"

What is the motivation or use case for changing the behavior?

Adding the theme by default is a convenience feature that ensures that the components are immediately ready for use. It becomes a problem when a custom theme is in use.

The schematic doesn't detect this scenario and will add a theme anyway. This results in an increased bundle size and styling issues.

Environment

N/A

/cc @gyoshev @rkonstantinov

[tsvetomir]

Update: The schematics have been updated to register the pre-built CSS files instead of SASS, improving build times and compatibility with IE.

Existing users are urged to replace the theme registration (2 instances) in angular.json with:

{
   "input": "node_modules/@progress/kendo-theme-default/dist/all.css"
}

[tsvetomir]

Update: Decided to drop the optional theme parameter as registering themes is a non-trivial task. For example, the user might be including styles for specific components, the file layout can be arbitrary, etc.

This limits the schematic to registering a theme only on first use, leaving the components in a fully functional state until the user decides to change or customize the theme. More importantly, it prevents the schematic from doing harm to existing projects.

[tsvetomir]

Fixed to register theme only on first install. No styles will be imported if the project has a dependency to any of the@progress/kendo-theme-* packages.