Promisify resolve-id

Author: TrySound

lib/resolve-id.js

@@ -7,48 +7,64 @@ var moduleDirectories = [
   "node_modules",
 ]
 
-module.exports = function(id, base, paths) {
-  try {
-    var resolveOpts = {
-      basedir: base,
-      moduleDirectory: moduleDirectories,
-      paths: paths,
-      extensions: [ ".css" ],
-      packageFilter: function processPackage(pkg) {
-        pkg.main = pkg.style || "index.css"
-        return pkg
-      },
-    }
-    var file
-    try {
-      file = resolve.sync(id, resolveOpts)
-    }
-    catch (e) {
-      // fix to try relative files on windows with "./"
-      // if it's look like it doesn't start with a relative path already
-      // if (id.match(/^\.\.?/)) {throw e}
-      try {
-        file = resolve.sync("./" + id, resolveOpts)
-      }
-      catch (err) {
-        // LAST HOPE
-        if (!paths.some(function(dir) {
-          file = path.join(dir, id)
-          return fs.existsSync(file)
-        })) {
-          throw err
+function isFilePromise(path) {
+  return new Promise(function(resolve, reject) {
+    fs.stat(path, function(err, stat) {
+      if (err) {
+        if (err.code === "ENOENT") {
+          return resolve(false)
         }
+        return reject(err)
       }
-    }
+      resolve(stat.isFile() || stat.isFIFO())
+    })
+  })
+}
 
-    return path.normalize(file)
-  }
-  catch (e) {
-    throw new Error([
-      "Failed to find '" + id + "'",
-      "in [ ",
-      "    " + paths.join(",\n        "),
-      "]",
-    ].join("\n    "))
+function resolvePromise(id, opts) {
+  return new Promise(function(res, rej) {
+    resolve(id, opts, function(err, path) {
+      if (err) {
+        return rej(err)
+      }
+      res(path)
+    })
+  })
+}
+
+module.exports = function(id, base, paths) {
+  var resolveOpts = {
+    basedir: base,
+    moduleDirectory: moduleDirectories,
+    paths: paths,
+    extensions: [ ".css" ],
+    packageFilter: function processPackage(pkg) {
+      pkg.main = pkg.style || "index.css"
+      return pkg
+    },
   }
+  return resolvePromise(id, resolveOpts).catch(function() {
+    // fix to try relative files on windows with "./"
+    // if it's look like it doesn't start with a relative path already
+    // if (id.match(/^\.\.?/)) {throw e}
+    return resolvePromise("./" + id, resolveOpts)
+  }).catch(function() {
+    // LAST HOPE
+    return Promise.all(paths.map(function(p) {
+      return isFilePromise(path.resolve(p, id))
+    })).then(function(results) {
+      for (var i = 0; i < results.length; i += 1) {
+        if (results[i]) {
+          return path.resolve(paths[i], id)
+        }
+      }
+
+      throw new Error([
+        "Failed to find '" + id + "'",
+        "in [ ",
+        "    " + paths.join(",\n        "),
+        "]",
+      ].join("\n    "))
+    })
+  })
 }