ADD support for multiple resolve directories

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+ "deepscan.enable": true
+}

README.md

@@ -34,6 +34,6 @@ import CoreJSUpgradeWebpackPlugin from 'corejs-upgrade-webpack-plugin';
 
 // add this to your webpack.plugins config
 new CoreJSUpgradeWebpackPlugin({
- resolveFrom: process.cwd(),
+ resolveFrom: [process.cwd()],
 });
 ```

src/index.ts

@@ -73,16 +73,18 @@ export const rewriteCoreJsRequest = (originalRequest: string, lowerVersion = fal
 };
 
 export interface Options {
- resolveFrom: string | false;
+ resolveFrom: string | false | string[];
 }
 
 const defaultOptions = {
  resolveFrom: false,
+ resolveBackup: false,
 } as Options
 
 export default function CoreJSUpgradeWebpackPlugin(options: Options) {
  options = Object.assign({}, defaultOptions, options || {});
- const resolve = options.resolveFrom ? resolveFrom.bind(null, options.resolveFrom) : require.resolve;
+
+ const resolvers = options.resolveFrom ? [].concat(options.resolveFrom).map(r => resolveFrom.bind(null, r)) : [];
 
  return new NormalModuleReplacementPlugin(/core-js/, resource => {
  const originalRequest = (resource.userRequest || resource.request) as string;
@@ -92,28 +94,39 @@ export default function CoreJSUpgradeWebpackPlugin(options: Options) {
  if (originalRequest.match(/@babel\/runtime\/core-js/)) {
  return;
  }
- 
+
  try {
  require.resolve(originalRequest);
  } catch (originalError) {
  let error = true;
 
- // attempt to upgrade the path from core-js v2 to v3
- if (error) {
- try {
- // eslint-disable-next-line no-param-reassign
- resource.request = resolve(rewriteCoreJsRequest(originalRequest));
- error = false;
- } catch (e) {}
- }
-
- // attempt to downgrade the path from es7 to es6
- if (error) {
- try {
- // eslint-disable-next-line no-param-reassign
- resource.request = resolve(rewriteCoreJsRequest(originalRequest, true));
- error = false;
- } catch (e) {}
+ for (const resolve of resolvers) {
+ // attempt the core-js v2 from backup
+ if (error) {
+ try {
+ // eslint-disable-next-line no-param-reassign
+ resource.request = resolve(originalRequest);
+ error = false;
+ } catch (e) {}
+ }
+
+ // attempt to upgrade the path from core-js v2 to v3 from backup
+ if (error) {
+ try {
+ // eslint-disable-next-line no-param-reassign
+ resource.request = resolve(rewriteCoreJsRequest(originalRequest));
+ error = false;
+ } catch (e) {}
+ }
+
+ // attempt to downgrade the path from es7 to es6 from backup
+ if (error) {
+ try {
+ // eslint-disable-next-line no-param-reassign
+ resource.request = resolve(rewriteCoreJsRequest(originalRequest, true));
+ error = false;
+ } catch (e) {}
+ }
  }
 
  if (error) {