add initial messy helper script for externals

scripts/webpack_externals.js

@@ -0,0 +1,102 @@
+// Copyright (c) Jupyter Development Team.
+// Distributed under the terms of the Modified BSD License.
+var path = require("path");
+
+function validate_lab_config(name, lab_pkg){
+  if(!lab_pkg["main"]){
+    throw Exception(name + " is not configured properly to load at runtime");
+  }
+
+  if(!lab_pkg["externals"]){
+    console.warn(name + " doesn't explicitly define its externals, will naively assume the package name");
+  }
+}
+
+
+function load_externals(pkg_path, pkg_name, lab_pkg, local_require){
+  if(!lab_pkg["externals"]){
+    return [pkg_name];
+  }
+
+  var pkg_externals = [pkg_name];
+
+  try {
+    pkg_externals = pkg_externals.concat(local_require(pkg_path + "/" + lab_pkg["externals"]));
+  } catch(err) {
+    console.warn("Couldn't load the externals for " + pkg_name +
+                 ", just using the package name");
+  }
+
+  return pkg_externals;
+}
+
+
+function find_externals(local_require, pkg_path, pkg_name, seen){
+  // an array of strings, functions or regexen that can be deferenced by
+  // webpack `externals` config directive
+  // https://webpack.github.io/docs/configuration.html#externals
+
+  var externals = [],
+    package_json,
+    is_user_pkg = arguments.length === 1,
+    // You should have `require('../package.json')`
+    seen = seen || {},
+    pkg_path = pkg_path || "";
+
+  if(is_user_pkg){
+    package_json = local_require("./package.json");
+    pkg_name = package_json["name"];
+  }else{
+    console.log("WHERE IS", pkg_name, pkg_path)
+    package_json = local_require(pkg_path + "/package.json");
+    console.log("HERE IS", pkg_name, pkg_path)
+  }
+
+  if(seen[pkg_name]){
+    return [];
+  }
+
+  // avoid circular dependencies
+  seen[pkg_name] = true;
+
+  var lab_config;
+
+  try {
+    lab_config = package_json["jupyter"]["lab"];
+  } catch(err) {
+    if(is_user_pkg){
+      throw Exception(
+        "The package " + package_json["name"] + " does not contain " +
+        "a jupyter configuration. Please see TODO: where?"
+      );
+    }
+    return [];
+  }
+
+  validate_lab_config(pkg_name, lab_config);
+
+  if(is_user_pkg){
+    externals = [
+      function(context, request, callback){ /* TODO: PHOSPHOR */ },
+      "jupyter-js-services",
+      /codemirror/
+    ];
+  } else {
+    externals.push(load_externals(pkg_path, pkg_name, lab_config, local_require));
+  }
+
+  // look through the dependencies, and add to externals anything that has
+  // a jupyter lab config (you must have installed them some other way)
+  Object.keys(package_json["dependencies"]).map(function(dep_name){
+    var dep_pkg;
+    externals = externals.concat(find_externals(
+      local_require,
+      !pkg_path ? dep_name : pkg_path + "/node_modules/" + dep_name,
+      dep_name,
+      seen));
+  });
+
+  return externals;
+}
+
+module.exports = find_externals;