Lesson 8Nx create your schematics

In this section, we will create a custom schematic that permits us to generate new libraries with our specific rule (type, scope, platform)!

> npm run nx -- generate @nrwl/workspace:workspace-generator tagged-library

tools/generators/tagged-library/schema.json

{
  "cli": "nx",
  "id": "tagged-library",
  "type": "object",
  "properties": {
    "name": {
      "type": "string",
      "description": "Library name",
      "$default": {
        "$source": "argv",
        "index": 0
      }
    },
    "type": {
      "type": "string",
      "description": "Type of the library",
      "enum": ["data-access", "feature", "ui", "util"],
      "default": "feature",
      "x-prompt": {
        "message": "What type of library is it?",
        "items": [
          {
            "value": "data-access",
            "label": "Data Access"
          },
          {
            "value": "feature",
            "label": "Feature"
          },
          {
            "value": "ui",
            "label": "Ui"
          },
          {
            "value": "util",
            "label": "Util"
          }
        ]
      }
    },
    "scope": {
      "type": "string",
      "description": "Scope of the library",
      "default": "shared",
      "x-prompt": "What app doest this library belong to?"
    },
    "platform": {
      "type": "string",
      "description": "Platform of the library",
      "enum": ["web", "node", "any"],
      "default": "web",
      "x-prompt": {
        "message": "What platform can this library run on?",
        "items": [
          {
            "value": "web",
            "label": "Web"
          },
          {
            "value": "node",
            "label": "Node"
          },
          {
            "value": "any",
            "label": "Any"
          }
        ]
      }
    },
    "directory": {
      "type": "string",
      "default": "",
      "x-prompt": "What is the directory?"
    },
    "prefix": {
      "type": "string",
      "default": "flw",
      "x-prompt": "What is the Prefix?"
    }
  },
  "required": ["name"]
}

tools/generators/tagged-library/schema.ts

export type TaggedLibrarySchemaOptions = {
  name: string
  type: 'data-access' | 'feature' | 'ui' | 'util'
  scope: 'shared' | string
  platform: 'web' | 'node' | 'any'
  directory?: string
  prefix?: string | null
}

tools/generators/tagged-library/index.ts

import { Tree, formatFiles, installPackagesTask } from '@nrwl/devkit'
import { wrapAngularDevkitSchematic } from '@nrwl/devkit/ngcli-adapter'
import { libraryGenerator } from '@nrwl/workspace/generators'
import { libraryGenerator as backendLibraryGenerator } from '@nrwl/nest'
import { TaggedLibrarySchemaOptions } from './schema'
function getTags(schema: TaggedLibrarySchemaOptions): string {
  return `type:${schema.type},scope:${schema.scope},platform:${schema.platform}`
}
function getLibraryGenerator(schema: TaggedLibrarySchemaOptions) {
  if (schema.platform === 'node') return backendLibraryGenerator
  if (schema.platform === 'web')
    return wrapAngularDevkitSchematic('@nrwl/angular', 'library')
  return libraryGenerator
}
export default async function (host: Tree, schema: TaggedLibrarySchemaOptions) {
  const libGenerator = getLibraryGenerator(schema)
  await libGenerator(host, { ...schema, tags: getTags(schema) })
  await formatFiles(host)
  return () => {
    installPackagesTask(host)
  }
}

> npm run nx workspace-schematic tagged-library test-library