Added an extra reference implementation for $.getScript

Author: fabiospampinato

docs/migration_guide.md

@@ -106,22 +106,7 @@ Cash can parse `<script>` tags and execute their code when they are attached to
 
 However we do not support script tags inside iframes or script tags with a `src` attribute.
 
-If you need to load arbitrary JavaScript files you could use something like this:
-
-```javascript
-function loadScript ( url ) {
-  return new Promise ( ( resolve, reject ) => {
-    const script = document.createElement ( 'script' );
-    const head = document.getElementsByTagName ( 'head' )[0];
-    const anchor = document.getElementsByTagName ( 'script' )[0];
-    script.async = true;
-    script.onload = resolve;
-    script.onerror = reject;
-    script.src = url;
-    head.insertBefore ( script, anchor );
-  });
-}
-```
+If you need to load arbitrary JavaScript files you can find a reference implementation for `$.getScript` [here](https://github.com/kenwheeler/cash/blob/master/src/extra/get_script.ts).
 
 ### No CSS auto-suffixing support for `zoom`
 

pacco.json

@@ -2,6 +2,7 @@
   "browsers": ["ie >= 10"],
   "components": {
     "core/export_esm": false,
+    "extra/get_script": false,
     "extra/shorthands": false
   },
   "paths": {

src/extra/get_script.ts

@@ -0,0 +1,23 @@
+
+// @require core/cash.ts
+// @require core/variables.ts
+
+function getScript ( url: string, success?: Function ): void {
+
+  const script = doc.createElement ( 'script' ),
+        $anchor = cash ( 'script' );
+
+  script.async = true;
+  script.src = url;
+
+  if ( success ) script.onload = () => success ();
+
+  $anchor.before ( script );
+
+}
+
+interface CashStatic {
+  getScript ( url: string, success?: Function ): void;
+}
+
+cash.getScript = getScript;