ng-bootstrap-form-validation

An Angular module that makes Bootstrap form validation easy.

Check out the demo!

Note: v9.0.0 is out and supports Angular 9!

Install

1. Install by running npm install ng-bootstrap-form-validation --save

2. Add NgBootstrapFormValidationModule.forRoot() to your app.module.ts imports:

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule , ReactiveFormsModule} from '@angular/forms';
import { AppComponent } from './app.component';

import { NgBootstrapFormValidationModule } from 'ng-bootstrap-form-validation';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    ReactiveFormsModule,
    NgBootstrapFormValidationModule.forRoot()
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

3. Add NgBootstrapFormValidationModule to other modules in your application:

import { NgModule } from '@angular/core';
import { OtherComponent } from './other.component';

import { NgBootstrapFormValidationModule } from 'ng-bootstrap-form-validation';

@NgModule({
  declarations: [
    OtherComponent
  ],
  imports: [
    NgBootstrapFormValidationModule
  ]
})
export class OtherModule { }

Note: If you are only using a single (app) module, then you will need to import both:

import { NgBootstrapFormValidationModule } from 'ng-bootstrap-form-validation';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    ...
    NgBootstrapFormValidationModule.forRoot(),
    NgBootstrapFormValidationModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

Basics

Default Errors

By default, the validators found on the Validators class from @angular/forms module are handled for you out of the box. All you need to do is import the module.

Usage

ng-bootstrap-form-validation works by using the form-group Bootstrap class on your divs as component selector, and projecting the content into a component which handles form validation feedback for you.

The has-error and has-success classes are automatically added or removed to your form-group based on whether or not the input is valid, and is both touched and dirty.

Validation messages appear when an input is dirty, touched, and has errors.

Submitting the form will iterate over all controls and mark them as touched and dirty to provide feedback to the user. Additionally, there is a validSubmit event on forms which you can bind to instead of submit to only fire off when the form is actually valid.

basic-example.component.ts

import {Component, OnInit} from "@angular/core";
import {FormControl, FormGroup, Validators} from "@angular/forms";

@Component({
  selector: 'app-basic-example',
  templateUrl: './basic-example.component.html',
  styleUrls: ['./basic-example.component.css']
})
export class BasicExampleComponent implements OnInit {

  formGroup: FormGroup;

  ngOnInit() {
    this.formGroup = new FormGroup({
      Email: new FormControl('', [
        Validators.required,
        Validators.pattern(/^[a-zA-Z0-9.!#$%&’*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/)
      ]),
      Password: new FormControl('', [
        Validators.required,
        Validators.minLength(8),
        Validators.maxLength(20)
      ])
    });
  }

  onSubmit() {
    console.log(this.formGroup);
  }

  onReset() {
    this.formGroup.reset();
  }

}

basic-example.component.html

<div class="row">
  <div class="col-md-6 col-md-offset-3">
    <form [formGroup]="formGroup" (validSubmit)="onSubmit()">
      <div class="form-group">
        <label class="control-label">Email</label>
        <input type="text" class="form-control" formControlName="Email">
      </div>
      <div class="form-group">
        <label class="control-label">Password</label>
        <input type="password" class="form-control" formControlName="Password">
      </div>
      <button class="btn btn-default" type="button" (click)="onReset()">Reset</button>
      <button class="btn btn-primary pull-right" type="submit">Submit</button>
    </form>
  </div>
</div>

Custom error message placement

Note: the <bfv-messsages></bfv-messages> component still must be placed within the <div class="form-group">.

basic-example.component.html

<div class="row">
  <div class="col-md-6 col-md-offset-3">
    <form class="form-horizontal" [formGroup]="formGroup" (validSubmit)="onSubmit()">
      <div class="form-group">
        <label class="control-label col-sm-2">Email</label>
        <div class="col-sm-10">
          <input type="text" class="form-control" formControlName="Email">
          <bfv-messages></bfv-messages>
        </div>
      </div>
      <div class="form-group">
        <label class="control-label col-sm-2">Password</label>
        <div class="col-sm-10">
          <input type="password" class="form-control" formControlName="Password">
          <bfv-messages></bfv-messages>
        </div>
      </div>
      <button class="btn btn-default" type="button" (click)="onReset()">Reset</button>
      <button class="btn btn-primary pull-right" type="submit">Submit</button>
    </form>
  </div>
</div>

Custom Error Messages

Module Level Custom Errors

You can provide an ErrorMessage array via the CUSTOM_ERROR_MESSAGES multi-provider in your module to provide custom errors across your module/app. In order for this to be AOT compatable, the function definitions must be exported. see below for an example

custom-errors.ts

import {ErrorMessage} from "ng-bootstrap-form-validation";

export const CUSTOM_ERRORS: ErrorMessage[] = [
  {
    error: "required",
    format: requiredFormat
  }, {
    error: "email",
    format: emailFormat
  }
];

export function requiredFormat(label: string, error: any): string {
  return `${label} IS MOST DEFINITELY REQUIRED!`;
}

export function emailFormat(label: string, error: any): string {
  return `${label} doesn't look like a valid email address.`;
}

app.module.ts

import {BrowserModule} from "@angular/platform-browser";
import {NgModule} from "@angular/core";
import {FormsModule, ReactiveFormsModule} from "@angular/forms";
import { HttpClientModule } from '@angular/common/http';
import {
  NgBootstrapFormValidationModule,
  CUSTOM_ERROR_MESSAGES
} from "ng-bootstrap-form-validation";
import {AppComponent} from "./app.component";
import {CUSTOM_ERRORS} from "./custom-errors";

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    ReactiveFormsModule,
    NgBootstrapFormValidationModule.forRoot(),
    HttpClientModule
  ],
  providers: [{
    provide: CUSTOM_ERROR_MESSAGES,
    useValue: CUSTOM_ERRORS,
    multi: true
  }],
  bootstrap: [AppComponent]
})
export class AppModule {
}

Form Control Specific Custom Errors

In addition to providing custom errors at the top level using the .forRoot() method, you can provide custom error messages to a specific control by binding to the customErrorMessages directive on the .form-group element. Modifying the basic example above, we can provide a one time custom error message to a specific .form-group. Unlike the global custom error messages, these functions do not need to be individually exported.

custom-error-example.component.ts

import {Component, OnInit} from "@angular/core";
import {FormControl, FormGroup, Validators} from "@angular/forms";
import {ErrorMessage} from "../../lib/Models/ErrorMessage";

@Component({
  selector: 'app-custom-errors',
  templateUrl: './custom-errors.component.html',
  styleUrls: ['./custom-errors.component.css']
})
export class CustomErrorsComponent implements OnInit {

  formGroup: FormGroup;

  customErrorMessages: ErrorMessage[] = [
    {
      error: 'required',
      format: (label, error) => `${label.toUpperCase()} IS DEFINITELY REQUIRED!`
    }, {
      error: 'pattern',
      format: (label, error) => `${label.toUpperCase()} DOESN'T LOOK RIGHT...`
    }
  ];

  ngOnInit() {
    this.formGroup = new FormGroup({
      Email: new FormControl('', [
        Validators.required,
        Validators.pattern(/^[a-zA-Z0-9.!#$%&’*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/)
      ]),
      Password: new FormControl('', [
        Validators.required,
        Validators.minLength(8),
        Validators.maxLength(20)
      ])
    });
  }

  onSubmit() {
    console.log(this.formGroup);
  }

  onReset() {
    this.formGroup.reset();
  }

}

custom-error-example.component.html

<div class="row">
  <div class="col-md-6 col-md-offset-3">
    <form [formGroup]="formGroup" (validSubmit)="onSubmit()">
      <div class="form-group" [customErrorMessages]="customErrorMessages">
        <label class="control-label">Email</label>
        <input type="text" class="form-control" formControlName="Email">
      </div>
      <div class="form-group">
        <label class="control-label">Password</label>
        <input type="password" class="form-control" formControlName="Password">
      </div>
      <button class="btn btn-default" type="button" (click)="onReset()">Reset</button>
      <button class="btn btn-primary pull-right" type="submit">Submit</button>
    </form>
  </div>
</div>

Roadmap

• Add out of the box support for ng2-validation validators