How to solve translation issues on a bilingual Shopify site?

Here’s an example from a different Theme where it suffices to add

Shopify.routes.root +

in front of the search query generating code inside the theme.js file.

Before:

this.getSearchQuery = () => {
      return `/search/suggest.json?q=${this.searchInput.value}&resources[limit]=3&resources[limit_scope]=each`;
    };

    this.getSearchPageUrlWithQuery = () => {
      return `/search?q=${encodeURIComponent(this.searchInput.value)}*`;
    };

After:

this.getSearchQuery = () => {
      return **Shopify.routes.root +** `search/suggest.json?q=${this.searchInput.value}&resources[limit]=3&resources[limit_scope]=each`;
    };

    this.getSearchPageUrlWithQuery = () => {
      return **Shopify.routes.root +** `search?q=${encodeURIComponent(this.searchInput.value)}*`;
    };