Build error in Svelte SPA

[style2joy]

While building the Client side SPA using Svelte (not SvelteKit), I get following error:

[rollup-plugin-svelte] The following packages did not export their "package.json" file so we could not check the "svelte" field. If you had difficulties importing svelte components from a package, then please contact the author and ask them to export the package.json file.

• is-promise

My app however still works. Please suggest if there's a way to fix this.