I am building a painter that can chain getters, but each getter can only be called once. For TextDecorator and BgDecorator, they are easy to handle because I can just return different classes. However, for StyleDecorator, since it is allowed to apply multiple styles, I don’t know how to define a type that can accumulate omitted getters. Please see the code below:

class Painter {
  protected textColor: string
  protected bgColor: string
  protected styles: string[]

  paint() {
    // paint the text
  }
  static create() {
    return new TextDecorator()
  }
}

class StyleDecorator extends Painter  {
  get bold(): Omit<StyleDecorator, 'bold'> {
    this.styles.push('bold')
    return this
  }
  get underline(): Omit<StyleDecorator, 'underline'> {
    this.styles.push('underline')
    return this
  }
  get italics(): Omit<StyleDecorator, 'italics'> {
    this.styles.push('italics')
    return this
  }
}

class BgDecorator extends StyleDecorator {
  get redBg(): StyleDecorator {
    this.bgColor = "red"
    return this
  }
  get blueBg(): StyleDecorator {
    this.bgColor = "blue"
    return this
  }
}

class TextDecorator extends BgDecorator {
  get white(): BgDecorator {
    this.textColor = "white"
    return this
  }
  get black(): BgDecorator {
    this.textColor = "black"
    return this
  }

}



Painter.create().white.redBg.bold.underline.paint() // ok
Painter.create().white.blueBg.bold.underline.bold.paint() // I want to see error that says bold cannot be called twice.
Painter.create().white.redBg.underline.bold.underline.paint() // I want to see error that says underline cannot be called twice.
Painter.create().white.redBg.italics.underline.italics.underline.paint() // I want to see error that says underline and italics cannot be called twice.

I looked at this by lukasgeiter and this by Titain they are close to what I want to achieve, but they are not getter and for me it is very difficult to understand how it works hence don’t even know how to modifi it..

Please help.