lang=ts splice

A .svelte file may carry two scripts, and they are not two ways of saying the same thing. <script lang="d"> is the libwasm struct. <script lang="ts">, whether instance or context="module", is TypeScript that Vite already understands. svelte-d does not compile that TypeScript. It splices the body into the workspace at src-ts/modules/generated/<identFromRel>.ts using js-module.ts.tmpl. Exported functions are wrapped as jsExports.env.<name>(...args) so libwasm.init can load them, and registered on window.__svelteD.ts[<ident>][<name>] so D can call them. If the body already exports jsExports, that bag is kept and only the registry trailer is appended. rewriteModulesIndex then regenerates src-ts/modules/index.ts from modules-index.ts.tmpl, folding every generated module into the same list that already contains bindings, spa, libwasm, and debug-bridge.

That regeneration is the splice. There is not a second index.ts, and there is not a Node require graph. Author import $ from 'jquery' inside the TS body is legal Vite input once the helper is on the workspace (see extensions). Same-file D calls those exports by the simple name — the printer emits a variadic callTs thunk. A printed import jquery in src-d/ would be a third FFI, and the wasm cell does not grow one.

The context="module" exports in the admin example (adminReady, adminLayoutReady) exist so tests and your own JS can name the page. They are registered on __svelteD.ts[<ident>_mod]. Dual-script files do both jobs. Another .svelte imports the printed D thunk (import lib.Bridge : greet). npm specifiers on the TS body fall through from the project onto dest package.json (declared range) and dest node_modules/<pkg> (a copy of the project’s install). See cross-calling and Cross-calling lang=d and lang=ts.