refactor: centralize domain values and enforce numeric lint

src/modules/auth/presentation/auth.dto.ts

@@ -7,20 +7,26 @@ import {
   ValidatorConstraint,
 } from 'class-validator';
 
+const MAX_EMAIL_LENGTH = 254;
+const ASCII_SPACE = 32;
+const ASCII_DELETE = 127;
+const MIN_PASSWORD_LENGTH = 12;
+const MAX_PASSWORD_BYTES = 72;
+
 @ValidatorConstraint({ name: 'email' })
 class EmailConstraint {
   validate(value: unknown): boolean {
     return (
       typeof value === 'string' &&
-      value.length <= 254 &&
+      value.length <= MAX_EMAIL_LENGTH &&
       value.split('@').length === 2 &&
       !value
         .split('')
         .some(
           (character) =>
             /\s/.test(character) ||
-            character.charCodeAt(0) < 32 ||
-            character.charCodeAt(0) === 127,
+            character.charCodeAt(0) < ASCII_SPACE ||
+            character.charCodeAt(0) === ASCII_DELETE,
         ) &&
       value.split('@').every(Boolean)
     );
@@ -33,7 +39,10 @@ class EmailConstraint {
 @ValidatorConstraint({ name: 'passwordBytes' })
 class PasswordBytesConstraint {
   validate(value: unknown): boolean {
-    return typeof value === 'string' && Buffer.byteLength(value, 'utf8') <= 72;
+    return (
+      typeof value === 'string' &&
+      Buffer.byteLength(value, 'utf8') <= MAX_PASSWORD_BYTES
+    );
   }
   defaultMessage(): string {
     return 'must not exceed 72 UTF-8 bytes';
@@ -49,9 +58,13 @@ export class CredentialsDto {
   @Validate(EmailConstraint)
   declare email: string;
 
-  @ApiProperty({ minLength: 12, maxLength: 72, example: 'a secure password' })
+  @ApiProperty({
+    minLength: MIN_PASSWORD_LENGTH,
+    maxLength: MAX_PASSWORD_BYTES,
+    example: 'a secure password',
+  })
   @IsString()
-  @MinLength(12)
+  @MinLength(MIN_PASSWORD_LENGTH)
   @Validate(PasswordBytesConstraint)
   declare password: string;
 }