Cleanup module resolution

Author: natefaubion

frame.html

@@ -13,18 +13,25 @@
   (function() {
     function evalPureScript(sources) {
       var modules = {};
+      function dirname(str) {
+        var ix = str.lastIndexOf("/");
+        return ix < 0 ? "" : str.slice(0, ix);
+      }
+      function resolvePath(a, b) {
+        if (b[0] === "." && b[1] === "/") {
+          return dirname(a) + b.slice(1);
+        }
+        if (b[0] === "." && b[1] === "." && b[2] === "/") {
+          return dirname(dirname(a)) + b.slice(2);
+        }
+        return b;
+      }
       return function load(name) {
         if (modules[name]) {
           return modules[name].exports;
         }
         function require(path) {
-          if (path === "./foreign.js") {
-            return load(name + "$Foreign");
-          }
-          if (path.indexOf("../") === 0) {
-            return load(path.slice(3).replace(/\/index\.js$/, ""));
-          }
-          return load(path);
+          return load(resolvePath(name, path));
         }
         var module = modules[name] = { exports: {} };
         new Function("module", "exports", "require", sources[name])(module, module.exports, require);

js/index.js

@@ -12,7 +12,7 @@ import Control.Monad.Except (ExceptT)
 import Control.Parallel (parTraverse)
 import Data.Array as Array
 import Data.Array.NonEmpty as NonEmpty
-import Data.Maybe (Maybe(..))
+import Data.Maybe (Maybe(..), fromMaybe)
 import Data.Newtype (unwrap)
 import Data.String (Pattern(..))
 import Data.String as String
@@ -45,7 +45,18 @@ type Dependency =
   }
 
 requireRegex :: Regex
-requireRegex = unsafeRegex """^var\s+\S+\s*=\s*require\(["']([^"']*)["']\);""" noFlags
+requireRegex = unsafeRegex """^var\s+\S+\s*=\s*require\(["']([^"']*)["']\)""" noFlags
+
+dirname :: String -> String
+dirname path = fromMaybe "" do
+  ix <- String.lastIndexOf (Pattern "/") path
+  pure $ String.take ix path
+
+resolvePath :: String -> String -> Maybe String
+resolvePath a b
+  | String.take 2 b == "./"  = Just $ dirname a <> String.drop 1 b
+  | String.take 3 b == "../" = Just $ dirname (dirname a) <> String.drop 2 b
+  | otherwise = Nothing
 
 parseDeps :: String -> JS -> Array Dependency
 parseDeps current = Array.mapMaybe go <<< String.split (Pattern "\n") <<< unwrap
@@ -54,14 +65,10 @@ parseDeps current = Array.mapMaybe go <<< String.split (Pattern "\n") <<< unwrap
   go line = do
     match <- Regex.match requireRegex line
     requirePath <- join $ NonEmpty.index match 1
-    pure $ case String.split (Pattern "/") requirePath of
-      [ ".", "foreign.js" ] ->
-        { name: current <> "$Foreign"
-        , path: Just $ current <> "/foreign.js"
-        }
-      [ "..", name, "index.js" ] ->
-        { name
-        , path: Just $ name <> "/index.js"
+    pure $ case resolvePath current requirePath of
+      Just path ->
+        { name: path
+        , path: String.stripPrefix (Pattern "/") path
         }
       _ ->
         { name: requirePath