[utils] [fix] ignore hashbang and BOM while parsing (#2431)

Author: silverwind

utils/CHANGELOG.md

@@ -5,6 +5,9 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 
 ## Unreleased
 
+### Fixed
+- [Fix] Ignore hashbang and BOM while parsing ([#2431], thanks [@silverwind])
+
 ## v2.7.3 - 2022-01-26
 
 ### Fixed
@@ -115,6 +118,7 @@ Yanked due to critical issue with cache key resulting from #839.
 ### Fixed
 - `unambiguous.test()` regex is now properly in multiline mode
 
+[#2431]: https://github.com/import-js/eslint-plugin-import/pull/2431
 [#2350]: https://github.com/import-js/eslint-plugin-import/issues/2350
 [#2343]: https://github.com/import-js/eslint-plugin-import/pull/2343
 [#2261]: https://github.com/import-js/eslint-plugin-import/pull/2261

utils/parse.js

@@ -42,6 +42,14 @@ function makeParseReturn(ast, visitorKeys) {
   return ast;
 }
 
+function stripUnicodeBOM(text) {
+  return text.charCodeAt(0) === 0xFEFF ? text.slice(1) : text;
+}
+
+function transformHashbang(text) {
+  return text.replace(/^#!([^\r\n]+)/u, (_, captured) => `//${captured}`);
+}
+
 exports.default = function parse(path, content, context) {
 
   if (context == null) throw new Error('need context to parse properly');
@@ -78,6 +86,10 @@ exports.default = function parse(path, content, context) {
   // require the parser relative to the main module (i.e., ESLint)
   const parser = moduleRequire(parserPath);
 
+  // replicate bom strip and hashbang transform of ESLint
+  // https://github.com/eslint/eslint/blob/b93af98b3c417225a027cabc964c38e779adb945/lib/linter/linter.js#L779
+  content = transformHashbang(stripUnicodeBOM(String(content)));
+
   if (typeof parser.parseForESLint === 'function') {
     let ast;
     try {