Preflight

app/docs/md/conventions/preflight.md

@@ -0,0 +1,103 @@
+---
+title: Preflight
+---
+
+
+The purpose of the preflight file is to supply default application state.
+It can also be used to customize data based on the request per route.
+
+Enhance looks for the preflight file in the root of your app.
+
+<doc-code filename="app/preflight.mjs">
+
+```bash
+app
+├── api ............... data routes
+│   └── index.mjs ..... override default preflight application state with api data
+└── preflight.mjs ..... pre-populate application state
+
+```
+</doc-code>
+
+The preflight function is passed the request object enabling you to customize data per requested route.
+API responses are merged with the default state returned from preflight allowing you to override default state with specific API data per request.
+
+### Basic example 
+
+<doc-code filename="app/preflight.mjs">
+
+  ```javascript
+  export default function Preflight ({ req }) {
+    return { /* ...Your data here */ }
+  }
+````
+</doc-code>
+
+
+
+### Example of setting the page title using preflight
+
+<doc-code filename="app/preflight.mjs">
+
+  ```javascript
+  export default function Preflight ({ req }) {
+    return {
+      pageTitle: getPageTitle(req.path),
+      account: {
+        username: 'bobsyouruncle',
+        id: '23jk24h24'
+      }
+    }
+  }
+
+  function getPageTitle (path) {
+    const titleMap = {
+      '/': 'Home',
+      '/about': 'About',
+      '/account': 'My Account'
+    }
+
+    return titleMap[path] || 'My App Name'
+  }
+````
+</doc-code>
+
+
+
+### Example of overriding default preflight data with an API response
+
+<doc-code filename="app/preflight.mjs">
+
+  ```javascript
+  export default function Preflight ({ req }) {
+    return {
+      pageTitle: getPageTitle(req.path),
+      account: {
+        username: 'bobsyouruncle',
+        id: '23jk24h24'
+      }
+    }
+  }
+````
+</doc-code>
+
+<doc-code filename="app/api/index.mjs">
+
+  ```javascript
+  export async function get() {
+    return {
+      json: {
+        account: {
+          username: 'thisshouldoverride',
+          id: '39nr34n2'
+        }
+      }
+    }
+  }
+````
+</doc-code>
+
+The account object will be overridden by the API response.
+
+
+

app/docs/nav-data.mjs

@@ -34,6 +34,7 @@ export const data = [
       'browser',
       'public',
       '404-errors',
+      'preflight',
     ],
   },
   {

scripts/dictionary.txt

@@ -57,6 +57,8 @@ preconfigured
 prepended
 preloaded
 preprocessing
+preflight
+Preflight
 rulese(t|ts)
 scaleMax
 scaleMin