/** * Structural not-implemented stubs: a replaced module must expose every symbol * its importers name (a missing CommonJS symbol degrades to `undefined` at call * time instead of failing at link time), and every one of those symbols must * report exactly what is unavailable when it is finally called. */ /** * Build a function that throws naming its module and symbol. The refusal is * also written to the console before it propagates: callers routinely swallow * these errors far from their cause, and the console line is what places the * failure while debugging a worker session. * * `Face` is the Node declaration this stub stands in for, so the replaced module * publishes the type its importers compile against. The value is one throwing * function whatever that declaration says: a caller reaches the throw before any * declared parameter, return value, or `new` result exists, so the assertion * below cannot be observed as a lie. It is a function expression rather than an * arrow because a stub standing in for a class must refuse under `new` too, and * an arrow has no construct behavior to reach. * @param module - module specifier being stubbed. * @param symbol - exported symbol name. * @returns the throwing stand-in, typed as the member it replaces. */ // eslint-disable-next-line @typescript-eslint/no-unnecessary-type-parameters -- only the return position carries the Node declaration export function notImplementedFail never>(module: string, symbol: string): Face { return (function refuse(): never { throw notAvailableError(module, symbol) }) as Face } /** * Build the refusal error and write it to the console first, for stubs that * cannot be a plain throwing function (constructors, methods on structural * fakes). * @param module - module specifier being stubbed. * @param symbol - unavailable member, named as the importer sees it. * @returns the error to throw. */ export function notAvailableError(module: string, symbol: string): Error { const message = `web-preview: ${module}.${symbol} is not available in the worker host` console.error(message) return new Error(message) }