feat: add string length validator

npm/ng-packs/packages/core/src/lib/tests/validators.spec.ts

@@ -2,6 +2,7 @@ import { FormControl } from '@angular/forms';
 import { validateRange } from '../validators';
 import { validateCreditCard } from '../validators/credit-card.validator';
 import { validateRequired } from '../validators/required.validator';
+import { validateStringLength } from '../validators/string-length.validator';
 
 describe('Validators', () => {
   describe('Credit Card Validator', () => {
@@ -110,4 +111,40 @@ describe('Validators', () => {
       expect(control.valid).toBe(true);
     });
   });
+
+  describe('String Length Validator', () => {
+    test.each`
+      input        | options                 | expected
+      ${null}      | ${undefined}            | ${null}
+      ${undefined} | ${undefined}            | ${null}
+      ${''}        | ${undefined}            | ${null}
+      ${null}      | ${{ minimumLength: 0 }} | ${null}
+      ${undefined} | ${{ minimumLength: 0 }} | ${null}
+      ${''}        | ${{ minimumLength: 0 }} | ${null}
+      ${null}      | ${{ minimumLength: 3 }} | ${{ minlength: 3 }}
+      ${undefined} | ${{ minimumLength: 3 }} | ${{ minlength: 3 }}
+      ${''}        | ${{ minimumLength: 3 }} | ${{ minlength: 3 }}
+      ${'ab'}      | ${{ minimumLength: 3 }} | ${{ minlength: 3 }}
+      ${'abp'}     | ${{ minimumLength: 3 }} | ${null}
+      ${'abp'}     | ${{ maximumLength: 2 }} | ${{ maxlength: 2 }}
+      ${'abp'}     | ${{ maximumLength: 3 }} | ${null}
+    `(
+      'should return $expected when input is $input and options are $options',
+      ({ input, options, expected }) => {
+        const control = new FormControl(input, [validateStringLength(options)]);
+        control.markAsDirty({ onlySelf: true });
+        control.updateValueAndValidity({ onlySelf: true, emitEvent: false });
+
+        expect(control.errors).toEqual(expected);
+      },
+    );
+
+    it('should return null when control is pristine', () => {
+      const invalidUrl = '';
+      const control = new FormControl(invalidUrl, [validateStringLength({ minimumLength: 3 })]);
+      // control is not dirty
+
+      expect(control.valid).toBe(true);
+    });
+  });
 });

npm/ng-packs/packages/core/src/lib/validators/index.ts

@@ -2,13 +2,16 @@ import { Validators } from '@angular/forms';
 import { validateCreditCard } from './credit-card.validator';
 import { validateRange } from './range.validator';
 import { validateRequired } from './required.validator';
+import { validateStringLength } from './string-length.validator';
 export * from './credit-card.validator';
 export * from './range.validator';
 export * from './required.validator';
+export * from './string-length.validator';
 
 export const AbpValidators = {
   creditCard: validateCreditCard,
   email: () => Validators.email,
   range: validateRange,
   required: validateRequired,
+  stringLength: validateStringLength,
 };

npm/ng-packs/packages/core/src/lib/validators/string-length.validator.ts

@@ -0,0 +1,34 @@
+import { AbstractControl, ValidatorFn } from '@angular/forms';
+
+export interface StringLengthError {
+  maxlength?: number;
+  minlength?: number;
+}
+
+export interface StringLengthOptions {
+  maximumLength?: number;
+  minimumLength?: number;
+}
+
+export function validateStringLength({
+  maximumLength = Infinity,
+  minimumLength = 0,
+}: StringLengthOptions = {}): ValidatorFn {
+  return (control: AbstractControl): StringLengthError | null => {
+    if (control.pristine) return null;
+
+    if (!control.value && minimumLength) return { minlength: minimumLength };
+
+    const value = String(control.value);
+
+    return getMinLengthError(value, minimumLength) || getMaxLengthError(value, maximumLength);
+  };
+}
+
+function getMaxLengthError(value: string, maxlength: number): StringLengthError {
+  return value.length > maxlength ? { maxlength } : null;
+}
+
+function getMinLengthError(value: string, minlength: number): StringLengthError {
+  return value.length < minlength ? { minlength } : null;
+}