How can I extend angular schematic properties?

Question

My question is it possible to extend schema properties?

What I tried:
collection.json

{
  "$schema": "http://schema.angular.io/schematics/collection/2",
  "name": "@my/schematics",
  "description": "my default collection, containing all schematics that are used normally",
  "schematics": {
    "library": {
      "extends": "@nrwl/angular:library", <--- extends nrwl library
      "aliases": [ "lib" ],
      "factory": "./library",
      "description": "Create my library.",
      "schema": "./library/schema.json"
    }
}

library/schema.json

{
  "$schema": "http://schema.angular.io/schematics/collection/2",
  "id": "SchematicsAngularLibrary",
  "title": "Create my library",
  "type": "object",
  "properties": {
    "legacy": {    <--- adds custom property
      "type": "boolean",
      "description": "Legacy mode",
      "default": false
    }
  },
  "required": []
}

and my simplified schematic library/index.ts

import { chain, externalSchematic, Rule, Tree, SchematicContext } from '@angular-devkit/schematics';

export default function(schema: Schema): Rule {
  return function(host: Tree, context: SchematicContext) {
    const isLegacyMode = schema.legacy; // <--- this is what I am trying to achieve

    return chain([
      externalSchematic('@nrwl/angular', 'library', options),
    ])(host, context);
  };
}

But it looks like schematic was not extended, because when I run
ng g lib megalib --unitTestRunner=jest --legacy
it throws this error:
Unknown option: '--legacy'

Why I want to extend (not to copy): when nrwl/angular schema and schematic code will be updated, I will get these changes too.

Environment:
angular/* 9.0.0-rc.8
@nrwl/* 8.11.1

UPD:

Also I tried to use $ref in combination with allOf, but it works only with http, see this issue.

How can I extend angular schematic properties?

0 Answers0