Fix sourcemap plugin (#1505)

esinstall/src/rollup-plugins/rollup-plugin-strip-source-mapping.ts

@@ -9,7 +9,9 @@ export function rollupPluginStripSourceMapping(): Plugin {
   return {
     name: 'snowpack:rollup-plugin-strip-source-mapping',
     transform: (code) => ({
-      code: code.replace(/[^'"`]\/\/+#\s*sourceMappingURL=.+$/gm, ''),
+      code: code
+        // [a-zA-Z0-9-_\*?\.\/\&=+%]: valid URL characters (for sourcemaps)
+        .replace(/\/\/#\s*sourceMappingURL=[a-zA-Z0-9-_\*\?\.\/\&=+%\s]+$/gm, ''),
       map: null,
     }),
   };

test/rollup-plugins.test.js

@@ -0,0 +1,49 @@
+const {
+  rollupPluginStripSourceMapping,
+} = require('../esinstall/lib/rollup-plugins/rollup-plugin-strip-source-mapping.js');
+
+describe('snowpack:rollup-plugin-strip-source-mapping', () => {
+  const tests = [
+    {
+      name: 'inline',
+      given: `console.log('foo');//# sourceMappingURL=js.map.js`,
+      expected: `console.log('foo');`,
+    },
+    {
+      name: 'end of file',
+      given: `console.log('foo');
+//# sourceMappingURL=js.map.js`,
+      expected: `console.log('foo');
+`,
+    },
+    {
+      name: 'middle of file',
+      given: `console.log('foo');
+//# sourceMappingURL=js.map.js
+console.log('bar');
+  //# sourceMappingURL=js.map.js`,
+      expected: `console.log('foo');
+
+console.log('bar');
+  `,
+    },
+    {
+      name: 'inside string', // leave alone
+      given: `const myString ='//# sourceMappingURL=js.map.js';`,
+      expected: `const myString ='//# sourceMappingURL=js.map.js';`,
+    },
+    {
+      name: 'es-module-shim', // leave alone
+      given: `    sourceMappingResolved = \`\n//# sourceMappingURL=\` + resolveUrl(sourceMapping.slice(21), load.r);`,
+      expected: `    sourceMappingResolved = \`\n//# sourceMappingURL=\` + resolveUrl(sourceMapping.slice(21), load.r);`,
+    },
+  ];
+
+  const {transform} = rollupPluginStripSourceMapping();
+
+  tests.forEach(({name, given, expected}) => {
+    it(name, () => {
+      expect(transform(given).code).toBe(expected);
+    });
+  });
+});