Skip to content
Schematics Documentation

Pre-Execution Inputs

Introduction

The most common way is when we need to show questions in the terminal and we need these answers before the function factory start.

Code section

For this purpose, we have a property inside collection named: schema

{
  "$schema": "../node_modules/@angular-devkit/schematics/collection-schema.json",
  "schematics": {
    "add": {
      "description": "Add the library to the project",
      "factory": "./builder-generate/add/add.factory#main",
      "schema": "./builder-generate/add/schema.json" <- this schema
    },
  }
}

This file will contain all the questions and It will send to the factory function as first parameter.

schema.json sample
{
  "$schema": "http://json-schema.org/schema",
  "$id": "EmptyFolder",
  "title": "Add an empty folder",
  "type": "object",
  "properties": {
    "name": {
      "type": "string",
      "description": "The name of the folder.",
      "$default": {
        "$source": "argv",
        "index": 0
      },
      "x-prompt": "What name would you like to use for the empty folder?"
    }
  },
  "additionalProperties": true,
  "required": [
    "name"
  ]
}
import {Tree, Rule, SchematicContext} from '@angular-devkit/schematics';
export function testFactory(
  options: {name: string} // this object parameter has all the properties contains in the schema.json.
): Rule {
  return (tree: Tree, context: SchematicContext)
}