With this change we refactor the Angular CLI and replace the underlying args parser and command builder. We choose to use Yargs as our parser and command builder of choice. The main advantages of Yargs over other command builders are;
- Highly configurable.
- We already use it in other packages such as the compiler-cli/dev-infra etc..
- Commands and options can be added during runtime. This is a requirement that is needed to support architect and schematics commands.
- Outstanding documentation.
- The possibility to parse args without parser configuration (Free form).
- Commands are built lazily based on the arguments passed.
BREAKING CHANGE:
Several changes in the Angular CLI commands and arguments handling.
- `ng help` has been removed in favour of the `—-help` option.
- `ng —-version` has been removed in favour of `ng version` and `ng v`.
- Deprecated camel cased arguments are no longer supported. Ex. using `—-sourceMap` instead of `—-source-map` will result in an error.
- `ng update`, `—-migrate-only` option no longer accepts a string of migration name, instead use `—-migrate-only -—name <migration-name>`.
- `—-help json` help has been removed.
Closes#20976, closes#16614 and closes#16241
Previously, the workspace configuration file was found and loaded by individual commands potentially multiple times. This change moves the initial workspace location discovery and loading of the workspace to the CLI startup. It also provides the workspace to each command so that the commands can reuse the already loaded and parsed workspace configuration.
The feature comes from the "x-deprecated" field in schemas (any schema that is used
to parse arguments), and can be a boolean or a string.
The parser now takes a logger and will warn users when encountering a deprecated
option. These options will also appear in JSON help.
SubCommands are not tied to the option that triggers them. They
contain a subset of a CommandDescription interface, with at least
a short and long description and usage notes. These are generated
from the subcommand schema (e.g. schematics in case of generate).
