Step wizard form

Question

I am making angular application with angular dynamic form where i need to split up the form into two parts.

In which i have input field firstname and lastname at first page and on click the next button the children which has email and dropdown needs to get loaded..

Html:

    <form (ngSubmit)="onSubmit()" [formGroup]="form">

        <div *ngFor="let question of questions" class="form-row">
            <ng-container *ngIf="question.children">
                <div [formArrayName]="question.key">
                    <div *ngFor="let item of form.get(question.key).controls; let i=index" [formGroupName]="i">
                        <div *ngFor="let item of question.children">
                            <app-question [question]="item" [form]="form.get(question.key).at(i)"></app-question>
                        </div>
                    </div>
                </div>
            </ng-container>
            <ng-container *ngIf="!question.children">
                <app-question [question]="question" [form]="form"></app-question>

            </ng-container>
        </div>

  <button (click)="goBack()"> Previous </button> &nbsp;
  <button (click)="addControls('myArray')"> Next </button> 

        <div class="form-row">
            <button type="submit" [disabled]="!form.valid">Save</button>
    </div>
  </form>

Ts:

  @Input() questions: QuestionBase<any>[] = [];
  form: FormGroup;
  payLoad = '';

  page: number = 0

  constructor(private qcs: QuestionControlService) { }

  ngOnInit() {
    this.form = this.qcs.toFormGroup(this.questions);
  }

  onSubmit() {
    this.payLoad = JSON.stringify(this.form.value);
  }
  addControls(control: string) {
    let question: any = this.questions.find(q => q.key == control);
    let children = question ? question.children : null;
    if (children)
      (this.form.get(control) as FormArray).push(this.qcs.toFormGroup(children))
  }
  removeControls(control: string){
    let array=this.form.get(control) as FormArray;
    array.removeAt(array.length-1);
  }

  goBack() {
    //Function to move to previous step
  }

Working demo :

https://stackblitz.com/edit/angular-x4a5b6-p4agaq

In this demo with code you can see on every click over add button the children (array) get appended to the below in the same page..

I am also having removeControl function which has,

  removeControls(control: string){
    let array=this.form.get(control) as FormArray;
    array.removeAt(array.length-1);
  }

To be clear i am not going to use this now and not going to remove anything anywhere.. Only thing is on click next the children via addControl function adds the children to next next page and on previous get back to previous step.

In order to append to the same page given in demo, it should move to next page and again on click the previous it should get to original state on every next click it should give a new email and dropdown and on previous a getback to previous step..

It should get moved like slider with sliding effect while moving forth and back..

Everything needs to be in pure angular and javascript/typescript based and there is no jquery .. As you could able to see in my demo i have not included any library or jquery..

Kindly help me to achieve the result.. Stucked for a long time..

Answer 1

Pass array in the goBack method which you want to remove

   <button (click)="goBack('myArray')"> Previous </button> &nbsp;    

Put this method in the component ts file

  goBack(control: string) {
    let question: any = this.questions.find(q => q.key == control);
     let children = question ? question.children : null;
    if (children)

      (this.form.get(control) as FormArray).removeAt(children.length-1)

  }

Answer 2

If you want to create stepper form you can project the form and use the formcontrol to connect the parentformgroup.

ParentComponent.ts

---

Next

name = 'Angular';
  eSave = true;
  form = new FormGroup({});
  step2 = new FormGroup({});
  nextForm = false;

  ngOnInit() {
    this.form.statusChanges.subscribe(s => this.eSave = true);
  }   
  moveToNext() {
    if (this.form.valid) {
      this.nextForm = true;
    }
  }   
  moveToPrevious() {
    this.nextForm = false;
  }
  save() {
    console.log(this.form);
    console.log(this.step2);
  }
  enableSave($event) {
    if ($event == 'VALID' && this.form.valid) {

      this.eSave = false;
    }
  }

ParentComponent.ts

 name = 'Angular'; eSave = true; form = new FormGroup({}); step2 = new FormGroup({}); nextForm = false; ngOnInit() { this.form.statusChanges.subscribe(s => this.eSave = true); } moveToNext() { if (this.form.valid) { this.nextForm = true; } } moveToPrevious() { this.nextForm = false; } save() { console.log(this.form); console.log(this.step2); } enableSave($event) { if ($event == 'VALID' && this.form.valid) { this.eSave = false; } } 

Example: https://stackblitz.com/edit/angular-nynvvr

Answer 3

Have try to reach your requirements : Except UI part. I hope you can handle you UI as your requirement.

TS :

    import { Component, Input, OnInit } from '@angular/core';
    import { FormGroup, FormArray } from '@angular/forms';

    import { QuestionBase } from './question-base';
    import { QuestionControlService } from './question-control.service';

    @Component({
      selector: 'app-dynamic-form',
      templateUrl: './dynamic-form.component.html',
      providers: [QuestionControlService]
    })
    export class DynamicFormComponent implements OnInit {

      @Input() questions: QuestionBase<any>[] = [];
      form: FormGroup;
      payLoad = '';

      page: number = 0;

      constructor(private qcs: QuestionControlService) { }

      ngOnInit() {
        this.form = this.qcs.toFormGroup(this.questions);
      }

      onSubmit() {
        this.payLoad = JSON.stringify(this.form.value);
      }
      addControls(control: string, index: any) {
        let array = this.form.get('myArray') as FormArray;
        if (array.length > this.page) {
          this.page = this.page + 1;
        } else {
          let question: any = this.questions.find(q => q.key == control);
          let children = question ? question.children : null;
          if (children)
            (this.form.get(control) as FormArray).push(this.qcs.toFormGroup(children))
          this.page = this.page + 1;
        }
      }
      removeControls(control: string) {
        let array = this.form.get(control) as FormArray;
        array.removeAt(array.length - 1);
      }

      goBack() {
        if (this.page > 0) {
          this.page = this.page - 1;
        }
        //let array = this.form.get('myArray') as FormArray;
        //array.removeAt(array.length - 1);
        //Function to move to previous step
      }

    }

HTML : 

<div>
    <form (ngSubmit)="onSubmit()" [formGroup]="form">

        <div *ngFor="let question of questions" class="form-row">
            <ng-container *ngIf="question.children">
                <div [formArrayName]="question.key">
                    <div *ngFor="let item of form.get(question.key).controls; let i=index" [formGroupName]="i">
            <ng-template [ngIf]="i + 1 == page"> 
              <div *ngFor="let item of question.children">
                <app-question [question]="item" [form]="form.get(question.key).at(i)"></app-question>
              </div>
            </ng-template>
                    </div>
                </div>
            </ng-container>
            <ng-container *ngIf="!question.children">
                <app-question [question]="question" [form]="form"></app-question>

            </ng-container>
        </div>

  <button (click)="goBack()"> Previous </button> &nbsp;
  <button (click)="addControls('myArray',i)"> Next </button> 

        <div class="form-row">
            <button type="submit" [disabled]="!form.valid">Save</button>
    </div>
  </form> <br>

  <pre>
{{form?.value|json}}
</pre>
</div>

This will help you showing one page at a time. It will create new one if no next form exists. And on clicking previous it will navigate to old form.

Answer 4

So, you want to remove lastly added control email and dropdown control from the form group array .

I have added the code into goBack() function to remove child form group controls.

Component:

  goBack() {
    //Function to move to previous step
    if(this.form.controls['myArray']){      
      const arr = <FormArray>this.form.controls.myArray;
      arr.removeAt(arr.length - 1);
    }
  }

Working demo : https://angular-x4a5b6-cc4kyr.stackblitz.io