extract node resolver to common module in lib

packages/electrode-archetype-react-app-dev/config/webpack/plugins/module-resolver.js

@@ -1,8 +1,7 @@
 "use strict";
 
 const Path = require("path");
-const requireAt = require("require-at");
-const optionalRequire = require("optional-require");
+const nodeResolver = require("../../../lib/node-resolver");
 
 /*
  * This is a webpack module resolver plugin to ensure that modules are resolved from
@@ -16,70 +15,25 @@ module.exports = class ModuleResolver {
     this.target = target;
   }
 
-  isModuleRequest(request) {
-    //
-    // If request is not an absolute/relative path then it's requiring a
-    // nodejs module.
-    //
-    if (Path.isAbsolute(request)) return false;
-
-    if (request === "." || request === "..") {
-      return false;
-    }
-
-    if (request.startsWith("../") || request.startsWith("./")) {
-      return false;
-    }
-
-    if (Path.sep !== "/") {
-      return !request.startsWith("." + Path.sep) || !request.startsWith(".." + Path.sep);
-    }
-
-    return true;
-  }
-
   apply(resolver) {
     const archetypeDir = Path.join(__dirname, "..", "..", "..");
 
     resolver.plugin(this.source, (req, callback) => {
-      //
-      // Let webpack's internal resolver deal with requiring non-modules
-      //
-      if (!this.isModuleRequest(req.request)) return callback();
-
       //
       // If require is NOT originated from a dir within node_modules, then
       // call require.resolve from within the archetype's directory
       // to make sure the instance the archetype depends on is resolved.
       //
       const atPath = req.path.indexOf(this.path) < 0 ? archetypeDir : req.path;
 
+      const result = nodeResolver.resolve(req.request, atPath);
+
       //
-      // If request is requiring for a module, then first try to resolve the
-      // module's real path by looking for its package.json, and then use that
-      // with request converted to a relative path without the module name part.
-      //
-      const splits = req.request.split("/");
-      const nameX = splits[0].startsWith("@") ? 2 : 1; // check for scoped module
-      const name = splits.slice(0, nameX).join("/");
-      //
-      // All modules must have package.json
+      // Let webpack's internal resolver deal with requiring non-modules
       //
-      const resolved = optionalRequire.resolve(
-        requireAt(atPath),
-        // ensure require request paths are POSIX
-        Path.posix.join(name, "package.json"),
-        false
-      );
-
-      if (!resolved) return callback();
-
-      splits.splice(0, nameX, ".");
+      if (result === undefined) return callback();
 
-      const obj = Object.assign({}, req, {
-        path: Path.dirname(resolved),
-        request: splits.join("/")
-      });
+      const obj = Object.assign({}, req, result);
 
       return resolver.doResolve(
         this.target,

packages/electrode-archetype-react-app-dev/lib/node-resolver.js

@@ -0,0 +1,61 @@
+"use strict";
+
+/* eslint-disable prefer-template */
+
+const Path = require("path");
+const requireAt = require("require-at");
+const optionalRequire = require("optional-require");
+
+function isModuleRequest(request) {
+  //
+  // If request is not an absolute/relative path then it's requiring a
+  // nodejs module.
+  //
+  if (Path.isAbsolute(request)) return false;
+
+  if (request === "." || request === "..") {
+    return false;
+  }
+
+  if (request.startsWith("../") || request.startsWith("./")) {
+    return false;
+  }
+
+  if (Path.sep !== "/") {
+    return !request.startsWith("." + Path.sep) || !request.startsWith(".." + Path.sep);
+  }
+
+  return true;
+}
+
+function resolve(req, atPath) {
+  if (!isModuleRequest(req)) return undefined;
+
+  const splits = req.split("/");
+  const nameX = splits[0].startsWith("@") ? 2 : 1; // check for scoped module
+  const name = splits.slice(0, nameX).join("/");
+
+  //
+  // All modules must have package.json
+  //
+  const resolved = optionalRequire.resolve(
+    requireAt(atPath),
+    // ensure require request paths are POSIX
+    Path.posix.join(name, "package.json"),
+    false
+  );
+
+  if (!resolved) return undefined;
+
+  splits.splice(0, nameX, ".");
+
+  return {
+    path: Path.dirname(resolved),
+    request: splits.join("/")
+  };
+}
+
+module.exports = {
+  isModuleRequest,
+  resolve
+};