From db5d1befe075e05857f7fa32c2d118430f860c79 Mon Sep 17 00:00:00 2001
From: Vlad Ivanov <vladivanov.dev@gmail.com>
Date: Mon, 24 Oct 2022 23:57:16 +0200
Subject: [PATCH] feat(loader): add functions support for locals

---
 src/loader.js | 15 +++++++++------
 src/utils.js  | 22 ++++++++++++++++++++++
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/src/loader.js b/src/loader.js
index 6de4e3d6..616b5abc 100644
--- a/src/loader.js
+++ b/src/loader.js
@@ -8,6 +8,8 @@ const {
   BASE_URI,
   SINGLE_DOT_PATH_SEGMENT,
   stringifyRequest,
+  stringifyLocals,
+  stringifyLocal,
 } = require("./utils");
 const schema = require("./loader-options.json");
 
@@ -38,7 +40,7 @@ const MiniCssExtractPlugin = require("./index");
 
 /**
  * @param {string} content
- * @param {{ loaderContext: import("webpack").LoaderContext<LoaderOptions>, options: LoaderOptions, locals: {[key: string]: string } | undefined }} context
+ * @param {{ loaderContext: import("webpack").LoaderContext<LoaderOptions>, options: LoaderOptions, locals: { [key: string]: string | function } | undefined }} context
  * @returns {string}
  */
 function hotLoader(content, context) {
@@ -95,7 +97,7 @@ function pitch(request) {
    * @returns {void}
    */
   const handleExports = (originalExports, compilation, assets, assetsInfo) => {
-    /** @type {{[key: string]: string } | undefined} */
+    /** @type {{[key: string]: string | function } | undefined} */
     let locals;
     let namedExport;
 
@@ -228,15 +230,16 @@ function pitch(request) {
         ? Object.keys(locals)
             .map(
               (key) =>
-                `\nexport var ${key} = ${JSON.stringify(
-                  /** @type {{[key: string]: string }} */
-                  (locals)[key]
+                `\nexport var ${key} = ${stringifyLocal(
+                  /** @type {{ [key: string]: string | function }} */ (locals)[
+                    key
+                  ]
                 )};`
             )
             .join("")
         : `\n${
             esModule ? "export default" : "module.exports ="
-          } ${JSON.stringify(locals)};`
+          } ${stringifyLocals(locals)};`
       : esModule
       ? `\nexport {};`
       : "";
diff --git a/src/utils.js b/src/utils.js
index 416b38c1..998de604 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -205,6 +205,26 @@ function getUndoPath(filename, outputPath, enforceRelative) {
     : append;
 }
 
+/**
+ *
+ * @param {string | function} value
+ * @returns {string}
+ */
+function stringifyLocal(value) {
+  return typeof value === "function" ? value.toString() : JSON.stringify(value);
+}
+
+/**
+ *
+ * @param {{ [key: string]: string | function }} object
+ * @returns {string}
+ */
+function stringifyLocals(object) {
+  return `{${Object.entries(object)
+    .map(([key, value]) => `${JSON.stringify(key)}:${stringifyLocal(value)}`)
+    .join(",")}}`;
+}
+
 module.exports = {
   trueFn,
   findModuleById,
@@ -216,5 +236,7 @@ module.exports = {
   BASE_URI,
   SINGLE_DOT_PATH_SEGMENT,
   stringifyRequest,
+  stringifyLocal,
+  stringifyLocals,
   getUndoPath,
 };