angular-docs-cn/public/docs/_examples/cb-dynamic-form/ts/app/question-control.service.ts

// #docregion
import { Injectable }   from '@angular/core';
import { FormBuilder, Validators } from '@angular/common';
import { QuestionBase } from './question-base';

@Injectable()
export class QuestionControlService {
  constructor(private fb: FormBuilder) { }

  toControlGroup(questions: QuestionBase<any>[] ) {
    let group = {};

    questions.forEach(question => {
      group[question.key] = question.required ? [question.value || '', Validators.required] : [question.value || ''];
    });
    return this.fb.group(group);
  }
}