exceljs · Siemienik · Apr 7, 2020 · Apr 1, 2020 · Apr 1, 2020
diff --git a/README.md b/README.md
@@ -197,11 +197,29 @@ require('core-js/modules/es.object.assign');
 require('core-js/modules/es.object.keys');
 require('regenerator-runtime/runtime');
 
-// ...
-
 const ExcelJS = require('exceljs/dist/es5');
 ```
 
+For IE 11, you'll also need a polyfill to support unicode regex patterns. For example,
+
+```js
+const rewritePattern = require('regexpu-core');
+const {generateRegexpuOptions} = require('@babel/helper-create-regexp-features-plugin/lib/util');
+
+const {RegExp} = global;
+try {
+  new RegExp('a', 'u');
+} catch (err) {
+  global.RegExp = function(pattern, flags) {
+    if (flags && flags.includes('u')) {
+      return new RegExp(rewritePattern(pattern, flags, generateRegexpuOptions({flags, pattern})));
+    }
+    return new RegExp(pattern, flags);
+  };
+  global.RegExp.prototype = RegExp;
+}
+```
+
 ## Browserify
 
 ExcelJS publishes two browserified bundles inside the dist/ folder:

diff --git a/_patch-fast-csv.js b/_patch-fast-csv.js
diff --git a/gruntfile.js b/gruntfile.js
@@ -21,11 +21,21 @@ module.exports = function(grunt) {
           },
         ],
       },
+      bundle: {
+        files: [
+          {
+            cwd: './build',
+            expand: true,
+            src: ['exceljs.bare.js', 'exceljs.js'],
+            dest: './dist/',
+          },
+        ],
+      },
     },
     browserify: {
       bare: {
         src: ['./build/lib/exceljs.bare.js'],
-        dest: './dist/exceljs.bare.js',
+        dest: './build/exceljs.bare.js',
         options: {
           browserifyOptions: {
             standalone: 'ExcelJS',
@@ -34,7 +44,7 @@ module.exports = function(grunt) {
       },
       bundle: {
         src: ['./build/lib/exceljs.browser.js'],
-        dest: './dist/exceljs.js',
+        dest: './build/exceljs.js',
         options: {
           browserifyOptions: {
             standalone: 'ExcelJS',
@@ -48,6 +58,7 @@ module.exports = function(grunt) {
     },
     terser: {
       options: {
+        sourceMap: true,
         output: {
           preamble: '/*! ExcelJS <%= grunt.template.today("dd-mm-yyyy") %> */\n',
         },
@@ -94,6 +105,6 @@ module.exports = function(grunt) {
     },
   });
 
-  grunt.registerTask('build', ['babel', 'browserify', 'terser', 'copy']);
+  grunt.registerTask('build', ['babel:dist', 'browserify', 'babel:bundle', 'terser', 'copy']);
   grunt.registerTask('ug', ['terser']);
 };
diff --git a/lib/exceljs.browser.js b/lib/exceljs.browser.js
@@ -1,9 +1,26 @@
 /* eslint-disable import/no-extraneous-dependencies,node/no-unpublished-require */
 require('core-js/modules/es.promise');
+require('core-js/modules/es.string.includes');
 require('core-js/modules/es.object.assign');
 require('core-js/modules/es.object.keys');
 require('regenerator-runtime/runtime');
 
+const rewritePattern = require('regexpu-core');
+const {generateRegexpuOptions} = require('@babel/helper-create-regexp-features-plugin/lib/util');
+
+const {RegExp} = global;
+try {
+  RegExp('a', 'u');
+} catch (err) {
+  global.RegExp = function(pattern, flags) {
+    if (flags && flags.includes('u')) {
+      return new RegExp(rewritePattern(pattern, flags, generateRegexpuOptions({flags, pattern})));
+    }
+    return new RegExp(pattern, flags);
+  };
+  global.RegExp.prototype = RegExp;
+}
+
 const ExcelJS = {
   Workbook: require('./doc/workbook'),
 };

diff --git a/package.json b/package.json
@@ -47,10 +47,9 @@
     "lint:fix": "prettier-eslint --write $(pwd)'/**/*.js'",
     "lint:staged": "lint-staged",
     "clean": "rm -rf build/ && rm -rf dist",
-    "patch:fast-csv": "node _patch-fast-csv.js",
     "benchmark": "node --expose-gc benchmark",
     "benchmark:debug": "node --expose-gc --inspect-brk --trace-deopt benchmark",
-    "build": "npm run patch:fast-csv && grunt build",
+    "build": "grunt build",
     "preversion": "npm run clean && npm run build && npm run test:all && npm run test:dist",
     "postversion": "git push --no-verify && git push --tags --no-verify"
   },
@@ -106,6 +105,7 @@
   "devDependencies": {
     "@babel/cli": "^7.6.4",
     "@babel/core": "^7.9.0",
+    "@babel/helper-create-regexp-features-plugin": "^7.8.8",
     "@babel/preset-env": "^7.9.0",
     "@types/chai": "^4.2.11",
     "@types/mocha": "^5.2.7",
@@ -139,6 +139,7 @@
     "prettier-eslint": "^9.0.0",
     "prettier-eslint-cli": "^5.0.0",
     "regenerator-runtime": "^0.13.5",
+    "regexpu-core": "^4.7.0",
     "semver": "^5.6.0",
     "ts-node": "^8.8.1",
     "typescript": "^3.8.3"