title: How to allow both uppercase and lowercase in nest.js DTO
body: <p>I need to allow the user to enter the property name in both upper and lower cases.
  For example,</p>
  <p><strong>DTO:</strong></p>
  <pre><code>import { ApiProperty } from &quot;@nestjs/swagger&quot;;
  import { IsDefined, Validate } from &quot;class-validator&quot;;
  
  export class DicomDto {
  
      @ApiProperty({ description: 'Image data' })
      @IsDefined()
      '7fe0,0010'?: string;
      
  }
  </code></pre>
  <p>Here I want the user can give input as both '7fe0,0010' or '7FE0,0010'. But the user should enter only one case either '7fe0,0010' or '7FE0,0010', not both at same time.</p>
  <p>For example,
  input should be,</p>
  <pre><code>{
    '7fe0,0010': &quot;imagedata&quot; or '7FE0,0010': &quot;imagedata&quot;
  }
  </code></pre>
  <p>but input should not be,</p>
  <pre><code>{
    '7fe0,0010': &quot;imagedata&quot;,
    '7FE0,0010': &quot;imagedata&quot;
  }
  </code></pre>
  <p>Could you please help me is there any chance.</p>