feat: Allow using matches from externals for regex matching (#825)

src/index.js

@@ -160,6 +160,7 @@ function ncc (
   const externalMap = (() => {
     const regexps = [];
     const aliasMap = new Map();
+    const regexCache = new Map();
 
     function set(key, value) {
       if (key instanceof RegExp)
@@ -169,9 +170,27 @@ function ncc (
 
     function get(key) {
       if (aliasMap.has(key)) return aliasMap.get(key);
-
-      const matchedRegex = regexps.find(regex => regex.test(key));
-      return matchedRegex !== null ? aliasMap.get(matchedRegex) : null;
+      if (regexCache.has(key)) return regexCache.get(key);
+
+      for (const regex of regexps) {
+        const matches = key.match(regex)
+
+        if (matches) {
+          let result = aliasMap.get(regex)
+
+          if (matches.length > 1) {
+            // allow using match from regex in result
+            // e.g. caniuse-lite(/.*) -> caniuse-lite$1
+            result = result.replace(/(\$\d)/g, (match) => {
+              const index = parseInt(match.substr(1), 10)
+              return matches[index] || match
+            })
+          }
+          regexCache.set(key, result)
+          return result
+        }
+      }
+      return null;
     }
 
     return { get, set };

test/unit.test.js

@@ -44,6 +44,7 @@ for (const unitTest of fs.readdirSync(`${__dirname}/unit`)) {
         'piscina': 'piscina',
         'externaltest': 'externalmapped',
         '/\\w+-regex/': 'regexexternal',
+        '/external-replace(/.*)/': 'external-replace/replaced$1'
       }
     }, opts)).then(
       async ({ code, assets, map }) => {
@@ -88,4 +89,3 @@ for (const unitTest of fs.readdirSync(`${__dirname}/unit`)) {
     )
   });
 }
-

test/unit/externals/input.js

@@ -1,6 +1,7 @@
 const external = require('externaltest');
 const regexpExternal = require('external-regex');
+const regexpExternalMatch = require('external-replace/some-file')
 
 console.log(external);
 console.log(regexpExternal);
-
+console.log(regexpExternalMatch);

test/unit/externals/output.js

@@ -1,6 +1,14 @@
 /******/ (() => { // webpackBootstrap
 /******/ 	var __webpack_modules__ = ({
 
+/***/ 378:
+/***/ ((module) => {
+
+"use strict";
+module.exports = require("external-replace/replaced/some-file");
+
+/***/ }),
+
 /***/ 830:
 /***/ ((module) => {
 
@@ -60,10 +68,11 @@ var __webpack_exports__ = {};
 (() => {
 const external = __nccwpck_require__(830);
 const regexpExternal = __nccwpck_require__(958);
+const regexpExternalMatch = __nccwpck_require__(378)
 
 console.log(external);
 console.log(regexpExternal);
-
+console.log(regexpExternalMatch);
 
 })();