setTheme does not load theme if `themePath` was not specified in the configuration

[Dmitry A. Efimenko]

Reproduction

Steps to reproduce:

1. Open this StackBlitz link
2. Observe that theme was not applied because themePath was not provided in the config.

Expected Behavior

What behavior were you expecting to see?

Theme should be loaded. I think specifying themePath in the configuration should be optional.

The application might have conditional logic for loading theme based on user preferences. There's no need to first load a theme that the user does not need, and then switch to a user-preferred theme.

Actual Behavior

What behavior did you actually see?

Theme is not loaded due to an error.

StackBlitz doesn't provide a good error stack trace. Here's what I get locally:

ERROR TypeError: Cannot set properties of undefined (setting 'href')
at HighlightLoader.setTheme (ngx-highlightjs.mjs:133:36)

This points to this line of code
The _themeLinkElement is undefined because loadTheme, which sets this variable, never got to run

Environment

• Angular: 15
• ngx-highlightjs: ^7.0.1
• Browser(s): Chrome
• Operating System (e.g. Windows, macOS, Ubuntu): Windows

[Murhaf Sousli]

Thanks for reporting! here is a fixed stackblitz with v8.0.0