How do I create a "chained" schematic?

Question

I don't know the correct term for what I need, so I will try to explain it as clear as possible.

In CLIs like sequelize-cli you can run either sequelize db:create or sequelize db:drop. I want to create two schematics whose first part is a command in itself, but if you add a second part it will execute a different schematic.

Specifically, I want to :

• Run mySchematic:migration and create a lot of files.
• Run mySchematic:migration:express and it will only create migrations for express.
• Run mySchematic:migration:hapi and it will only create migrations for hapi.

I know how to achieve the functionality, but I am not able to get it to execute the different commands. When I run mySchematic:migration:hapi, the schematic that is executed is always mySchematic:migration.

This is my collection.json:

{
  "$schema": "../node_modules/@angular-devkit/schematics/collection-schema.json",
  "schematics": {
    "migration": {
      "description": "description.",
      "factory": "./migrations/index#migration",
      "schema": "./migrations/migration-schema.json"
    },
    "migration:express": {
      "description": "description.",
      "factory": "./migrations/index#express",
      "schema": "./migrations/express-schema.json"
    },
  },
  "migration:hapi": {
    "description": "description.",
    "factory": "./migrations/index#hapi",
    "schema": "./migrations/hapi-schema.json"
  },
}

Changing the order of the schematics does not work either.

I have also tried this, but it didn't work either:

{
  "$schema": "../node_modules/@angular-devkit/schematics/collection-schema.json",
  "schematics": {
    "migration": {
      "description": "description.",
      "factory": "./migrations/index#migration",
      "schema": "./migrations/migration-schema.json",
      "express": {
        "description": "description.",
        "factory": "./migrations/index#express",
        "schema": "./migrations/express-schema.json"
      },
      "hapi": {
        "description": "description.",
        "factory": "./migrations/index#hapi",
        "schema": "./migrations/hapi-schema.json"
      }
    }
  }
}