refactor: add reversedChartMapper support

Author: JounQin

src/utils.js

@@ -259,8 +259,10 @@ function normalizePath(file) {
   return path.sep === "\\" ? file.replace(/\\/g, "/") : file;
 }
 
+const reversedChartMapper = {};
+
 // eslint-disable-next-line no-control-regex
-const filenameReservedRegex = /[<>:"/\\|?*\s]/g;
+const filenameReservedRegex = /([<>:"/\\|?*\s])/g;
 // eslint-disable-next-line no-control-regex
 const reControlChars = /[\u0000-\u001f\u0080-\u009f]/g;
 
@@ -270,7 +272,21 @@ function escapeLocalIdent(localident) {
     localident
       // For `[hash]` placeholder
       .replace(/^((-?[0-9])|--)/, "_$1")
-      .replace(filenameReservedRegex, "-")
+      .replace(filenameReservedRegex, (_, $1) => {
+        // normalize Windows path `\` as unix `/` for constancy
+        const char = $1 === "\\" && path.sep === "\\" ? "/" : $1;
+
+        if (reversedChartMapper[char]) {
+          return reversedChartMapper[char];
+        }
+
+        const hex = char.charCodeAt(0).toString(16).toUpperCase();
+        const escaped = `\\C${hex}`;
+
+        reversedChartMapper[char] = escaped;
+
+        return escaped;
+      })
       .replace(reControlChars, "-")
       .replace(/\./g, "-"),
   );

test/__snapshots__/modules-option.test.js.snap

@@ -0,0 +1,7 @@
+a-b {
+  color: red;
+}
+
+a\C20b /* i.e. with spaces */ {
+  color: red;
+}

test/fixtures/modules/issue-1626/source.css

@@ -0,0 +1,5 @@
+import * as css from './source.css';
+
+__export__ = css.default;
+
+export default css;

test/fixtures/modules/issue-1626/source.js

@@ -2692,4 +2692,20 @@ describe('"modules" option', () => {
     expect(getWarnings(stats)).toMatchSnapshot("warnings");
     expect(getErrors(stats)).toMatchSnapshot("errors");
   });
+
+  it("issue #1626", async () => {
+    const compiler = getCompiler("./modules/issue-1626/source.js", {
+      modules: true,
+    });
+    const stats = await compile(compiler);
+
+    expect(
+      getModuleSource("./modules/issue-1626/source.css", stats),
+    ).toMatchSnapshot("module");
+    expect(getExecutedCode("main.bundle.js", compiler, stats)).toMatchSnapshot(
+      "result",
+    );
+    expect(getWarnings(stats)).toMatchSnapshot("warnings");
+    expect(getErrors(stats)).toMatchSnapshot("errors");
+  });
 });