A colleague asked me for help with a specific Angular build error he got. Everything was working fine during development but when he tried to create a production build using ng build --configuration production --aot
it failed with the following error message
Index html generation failed.
Let's have a look at the configuration in the angular.json
:
If we compare this configuration with the development version the biggest difference between the two is that for production the optimization
setting was enabled.
Let’s have a look inside the documentation to see what this setting does:
This option enables various optimizations of the build output, including:
- Minification of scripts and styles
- Tree-shaking
- Dead-code elimination
- Inlining of critical CSS
- Fonts inlining
Aha! I could guess where the problem appears. As we had removed the index.html from our Angular project (we are not using the default index.html but have an ASP.NET Core MVC page that is used to serve the necessary scripts and styling), the inlining part of the optimization is probably causing the issue. As the inlined CSS cannot be written to a file that doesn’t exist, it fails with the error message above.
To fix it, we had to finetune the optimization settings and disable the inlining: