typescript - Password validation is not working in Angular 5

Question

I am new to angular 5 ,Here I am trying to validate user password based on some conditions .

1. Minimum six characters, at least one letter and one number
2. Minimum eight characters, at least one letter, one number and one special character
3. Minimum eight characters, at least one uppercase letter, one lowercase letter and one number

User can choose one of the above pattern for the password field the validation error message will change accordingly.

For me non of the above conditions are working correctly.

can anyone help me to solve this .

Note : if I give the pattern directly in HTML's it is working correctly

app.component.html

<mat-form-field class="col-sm-12">
    <mat-label>Enter your password</mat-label>
    <input matInput placeholder="Password" [pattern]="patternNormal" [formControl]="fPassword" placeholder="Password" required>
    <mat-error *ngIf="fPassword.errors?.required">Please fill out this field</mat-error>
    <mat-error *ngIf="fPassword.errors&&fPassword.errors.pattern">{{errorMgs}}</mat-error>
</mat-form-field>

app.component.ts

export class SnackBarOverviewExample {

  //Minimum six characters, at least one letter and one number:
  patternNormal: any = "^(?=.*[A-Za-z])(?=.*d)[A-Za-zd]{6,}$";

  //Minimum eight characters, at least one letter, one number and one special character:
  patternMedium: any = "^(?=.*[A-Za-z])(?=.*d)(?=.*[$@$!%*#?&])[A-Za-zd$@$!%*#?&]{8,}$";

  //Minimum eight characters, at least one uppercase letter, one lowercase letter and one number:
  patternHign: any = "^(?=.*[a-z])(?=.*[A-Z])(?=.*d)(?=.*[$@$!%*?&])[A-Za-zd$@$!%*?&]{8,}";

  fEmail = new FormControl();
  fPassword = new FormControl();
  errorMgs: string;
  selectedPattern: string;
  constructor(private _formBuilder: FormBuilder) { }

  ngOnInit() {
    this.selectedPattern = 'patternNormal'; //will change based on user preference

    if (this.selectedPattern === 'patternNormal') {
      this.errorMgs = 'Password must have min 6 char,atleast 1 num and 1 char'
    } else if (this.selectedPattern === 'patternMedium') {
      this.errorMgs = 'Minimum eight characters, at least one letter, one number and one special character'
    } else if (this.selectedPattern === 'patternHign') {
      this.errorMgs = 'Minimum eight characters, at least one uppercase letter, one lowercase letter and one number'
    }

  }

Stackblitz URL :https://stackblitz.com/edit/angular-stacb4-5oaagd?file=app%2Fsnack-bar-overview-example.ts

Update :

1,sample value for first pattern - abcde1 (showing error but same value is accepted when I give the pattern directly in HTML).

Answer 1

There are a couple of issues:

• Double all the backslashes in the patterns, e.g. d => \d.
• There is no need using two $ in character classes. Keep just one occurrence as [$$$$$$] = [$].
• this.selectedPattern = 'patternNormal'; should be changed to this.selectedPattern = this.patternNormal; and the same should be done to all similar lines. These are variables and should not be used as string literals.

See the updated demo.

Code changes:

//Minimum six characters, at least one letter and one number:
patternNormal: any = "^(?=.*[A-Za-z])(?=.*\d)[A-Za-z\d]{6,}$";

//Minimum eight characters, at least one letter, one number and one special character:
patternMedium: any = "^(?=.*[A-Za-z])(?=.*\d)(?=.*[@$!%*#?&])[A-Za-z\d@$!%*#?&]{8,}$";

//Minimum eight characters, at least one uppercase letter, one lowercase letter and one number:
patternHign: any = "^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]{8,}$";

and

ngOnInit() {
    this.selectedPattern = this.patternNormal; //will change based on user preference

    if (this.selectedPattern === this.patternNormal) {
      this.errorMgs = 'Password must have min 6 char,atleast 1 num and 1 char'
    } else if (this.selectedPattern === this.patternMedium) {
      this.errorMgs = 'Minimum eight characters, at least one letter, one number and one special character'
    } else if (this.selectedPattern === this.patternHign) {
      this.errorMgs = 'Minimum eight characters, at least one uppercase letter, one lowercase letter and one number'
    }

  }