fix: make errors serializable

lint-staged.config.js

@@ -1,4 +1,4 @@
 module.exports = {
-  "*": ["prettier --write --ignore-unknown", "cspell"],
+  "*": ["prettier --write --ignore-unknown", "cspell --no-must-find-files"],
   "*.{js}": ["eslint --cache --fix"],
 };

src/index.js

@@ -6,8 +6,8 @@ import {
   isUnsupportedUrl,
   normalizeSourceMap,
   getLessImplementation,
+  errorFactory,
 } from "./utils";
-import LessError from "./LessError";
 
 async function lessLoader(source) {
   const options = this.getOptions(schema);
@@ -78,7 +78,7 @@ async function lessLoader(source) {
       this.addDependency(path.normalize(error.filename));
     }
 
-    callback(new LessError(error));
+    callback(errorFactory(error));
 
     return;
   } finally {

src/utils.js

@@ -240,9 +240,46 @@ function getLessImplementation(loaderContext, implementation) {
   return resolvedImplementation;
 }
 
+function getFileExcerptIfPossible(error) {
+  if (typeof error.extract === "undefined") {
+    return [];
+  }
+
+  const excerpt = error.extract.slice(0, 2);
+  const column = Math.max(error.column - 1, 0);
+
+  if (typeof excerpt[0] === "undefined") {
+    excerpt.shift();
+  }
+
+  excerpt.push(`${new Array(column).join(" ")}^`);
+
+  return excerpt;
+}
+
+function errorFactory(error) {
+  const message = [
+    "\n",
+    ...getFileExcerptIfPossible(error),
+    error.message.charAt(0).toUpperCase() + error.message.slice(1),
+    error.filename
+      ? `      Error in ${path.normalize(error.filename)} (line ${
+          error.line
+        }, column ${error.column})`
+      : "",
+  ].join("\n");
+
+  const obj = new Error(message, { cause: error });
+
+  obj.stack = null;
+
+  return obj;
+}
+
 export {
   getLessOptions,
   isUnsupportedUrl,
   normalizeSourceMap,
   getLessImplementation,
+  errorFactory,
 };