Make instructions for copying cMaps work with Yarn PnP, update sample and test suites

Author: wojtekmaj

README.md

@@ -173,6 +173,7 @@ npm install copy-webpack-plugin --save-dev
 Now, in your Webpack config, import the plugin:
 
 ```js
+import path from 'path';
 import CopyWebpackPlugin from 'copy-webpack-plugin';
 ```
 
@@ -181,7 +182,7 @@ and in `plugins` section of your config, add the following:
 ```js
 new CopyWebpackPlugin([
   {
-    from: 'node_modules/pdfjs-dist/cmaps/',
+    from: path.join(path.dirname(require.resolve('pdfjs-dist/package.json')), 'cmaps'),
     to: 'cmaps/'
   },
 ]),

sample/webpack4/webpack.config.js

@@ -6,6 +6,8 @@ const HtmlWebpackPlugin = require('html-webpack-plugin');
 
 const isProduction = process.env.NODE_ENV === 'production';
 
+const cMapsDir = path.join(path.dirname(require.resolve('pdfjs-dist/package.json')), 'cmaps');
+
 module.exports = {
   mode: isProduction ? 'production' : 'development',
   bail: isProduction,
@@ -56,7 +58,7 @@ module.exports = {
     new CopyWebpackPlugin({
       patterns: [
         { from: './sample.pdf' },
-        { from: 'node_modules/pdfjs-dist/cmaps/', to: 'cmaps/' },
+        { from: cMapsDir, to: 'cmaps/' },
       ],
     }),
   ],

sample/webpack5/webpack.config.js

@@ -6,6 +6,8 @@ const HtmlWebpackPlugin = require('html-webpack-plugin');
 
 const isProduction = process.env.NODE_ENV === 'production';
 
+const cMapsDir = path.join(path.dirname(require.resolve('pdfjs-dist/package.json')), 'cmaps');
+
 module.exports = {
   mode: isProduction ? 'production' : 'development',
   bail: isProduction,
@@ -56,7 +58,7 @@ module.exports = {
     new CopyWebpackPlugin({
       patterns: [
         { from: './sample.pdf' },
-        { from: 'node_modules/pdfjs-dist/cmaps/', to: 'cmaps/' },
+        { from: cMapsDir, to: 'cmaps/' },
       ],
     }),
   ],

test/webpack.config.js

@@ -8,6 +8,8 @@ const ReactRefreshWebpackPlugin = require('@pmmmwh/react-refresh-webpack-plugin'
 const isProduction = process.env.NODE_ENV === 'production';
 const isDevelopment = !isProduction;
 
+const cMapsDir = path.join(path.dirname(require.resolve('pdfjs-dist/package.json')), 'cmaps');
+
 module.exports = {
   mode: isProduction ? 'production' : 'development',
   bail: isProduction,
@@ -67,7 +69,7 @@ module.exports = {
     new CopyWebpackPlugin({
       patterns: [
         'test.pdf',
-        { from: '../node_modules/pdfjs-dist/cmaps/', to: 'cmaps/' },
+        { from: cMapsDir, to: 'cmaps/' },
       ],
     }),
     new HtmlWebpackPlugin({