ensure conditional type works with default value

[dwelle]

This fixes the return type of fileOpen when options.multiple is undefined (false by default).

[RReverser]

Note that a slightly simpler but still working option could've been to only add the = false part:

export function fileOpen<M extends boolean = false>(options?: {
  /** Acceptable MIME types. [] */
  mimeTypes?: string[];
  /** Acceptable file extensions. Defaults to "". */
  extensions?: string[];
  /** Suggested file description. Defaults to "". */
  description?: string;
  /** Allow multiple files to be selected. Defaults to false. */
  multiple?: M;
}): M extends true ? Promise<File> : Promise<File[]>;

[tomayac]

👍 Happy to merge a quick PR.

[dwelle]

Note that a slightly simpler but still working option could've been to only add the = false part:

That won't work when you explicitly specify multiple: undefined. An edge case, but correct.