How to declare module type for Typescript?

[BoldyrevDA]

There are different ways to import css by rollup-plugin-import-css.

So, this way

import styles from "./styles.css"; /* import the styles as a string */

I described in declaration.d.ts as

declare module "*.css" {
   const css: string;
   export default css;
}

But is there way to declare import with assertion?

import styles from "./styles.css" assert { type: "css" }; /* import the styles as a CSSStyleSheet */

[jleeson]

@BoldyrevDA Unfortunately it does not appear that TypeScript currently has a way to declare ambient declarations for import assertions. You can read more on that at microsoft/TypeScript#46135

However depending on your use for this plugin, you can change the import behavior of the string import to be a CSS Module rather than using assert syntax. In order to do this, add the modules: true option to the plugin config, and then you should be able to update your declaration.d.ts with the following:

declare module "*.css" {
   const stylesheet: CSSStyleSheet;
  export default stylesheet;
}

Its worth noting that when using modules: true, your css imports will be non-standard and importing styles as a string will not work anymore.

[jleeson]

Closing this since its a question regarding TypeScript syntax support.