The recently introduced typings-only mode in ngcc would incorrectly
write compiled JavaScript files if typings-only mode was requested, in
case the typings of the entry-point had already been processed in a
prior run of ngcc. The corresponding format property for which the
JavaScript files were written were not marked as processed, though, as
the typings-only mode excluded the format property itself from being
marked as processed. Consequently, subsequent runs of ngcc would not
consider the entry-point to have been processed and recompile the
JavaScript bundle once more, resulting in duplicate ngcc imports.
Fixes#41198
PR Close#41209
Some tools (such as Language Server and ng-packagr) only care about
the processed typings generated by ngcc. Forcing these tools to process
the JavaScript files as well has two disadvantages:
First, unnecessary work is being done, which is time consuming.
But more importantly, it is not always possible to know how the final bundling
tools will want the processed JavaScript to be configured. For example,
the CLI would prefer the `--create-ivy-entry-points` option but this would
break non-CLI build tooling.
This commit adds a new option (`--typings-only` on the command line, and
`typingsOnly` via programmatic API) that instructs ngcc to only render changes
to the typings files for the entry-points that it finds, and not to write any
JavaScript files.
In order to process the typings, a JavaScript format will need to be analysed, but
it will not be rendered to disk. When using this option, it is best to offer ngcc a
wide range of possible JavaScript formats to choose from, and it will use the
first format that it finds. Ideally you would configure it to try the `ES2015` FESM
format first, since this will be the most performant.
Fixes#40969
PR Close#40976
The `Logger` interface and its related classes are general purpose
and could be used by other tooling. Moving it into ngtsc is a more
suitable place from which to share it - similar to the FileSystem stuff.
PR Close#37114
