The .d.ts format does not preserve information about the Decorators applied to symbols. Some tools, such as Angular 2 template compiler, need access to statically analyzable information about Decorators, so this library allows programs to produce a foo.metadata.json to accompany a foo.d.ts file, and preserves the information that was lost in the declaration emit.

$ gulp build.tools
$ cp tools/metadata/package.json dist/tools/metadata/
$ npm login [angularcore]
$ npm publish dist/tools/metadata