fix(inertia-sails): ensure locals are accessible via locals.xxx in EJS templates

Sails's default EJS renderer creates an `options.locals` object for internal
helpers (blocks, layout, partial). EJS wraps templates in `with(data) { ... }`,
which causes `locals` inside the template to resolve to `data.locals` (the
Sails-created object) rather than the function parameter containing the actual
view data. This made `<%= locals.title %>` always return undefined.

Fix by pre-populating `data.locals` with user-provided locals so they survive
the `with` scoping.

Closes #188

Author: DominusKelvin

packages/inertia-sails/lib/render.js

@@ -32,6 +32,15 @@ module.exports = async function render(req, res, data) {
     return res.json(page)
   } else {
     // Implements full page reload
-    return res.view(rootView, { page, ...allLocals })
+    //
+    // We pass locals both as top-level properties AND nested under a `locals`
+    // key. This is necessary because Sails's default EJS renderer creates an
+    // `options.locals` object (for blocks, layout, partial helpers). EJS wraps
+    // templates in `with(data) { ... }`, so inside the template `locals`
+    // resolves to `data.locals` (the nested object) rather than the `locals`
+    // function parameter. By pre-populating `data.locals` with our values,
+    // `<%= locals.title %>` in the EJS template correctly resolves to the
+    // dynamic value instead of undefined.
+    return res.view(rootView, { page, ...allLocals, locals: { ...allLocals } })
   }
 }