如果我将“variant”设置为oprial,我会得到“Type'undefined'不能用作索引类型”

在typescript react原生项目中,这是我设置的组件:

    type Variants = "body" | "label" | "caption" | "error" | "hint";
    
    interface TextProps {
      theme?: DefaultTheme;
      // variant?: Omit<keyof Variants, undefined>;
      variant?: Variants;
    }
    
    export const Text = styled.Text<TextProps>`
      ${({ theme }) => defaultTextStyles(theme)}
      // HERE IS THE ISSUE "variants[variant](theme)"
      ${({ variant, theme }) => variants[variant](theme)}
    `;
    
    Text.defaultProps = {
      variant: "body",
    };

如果我设定 variant?: Variants 可选,我从 ${({ variant, theme }) => variants[variant](theme) .由于“variant”是可选的,它可以是未定义的,因此未定义不能用作索引。但我也设定了

   Text.defaultProps = {
      variant: "body",
    };

默认变量应该是“body”,但这不会生效。我试过了,但没用

    Text.defaultProps = {
      variant: "body",
    } as Partial<TextProps>;

Text.defaultProps = {
  variant: "body",
} as Pick<TextProps, "variant">;