Re-organize package URL parsing

server/utils/parsePackageURL.js

@@ -0,0 +1,39 @@
+const url = require('url')
+
+const URLFormat = /^\/((?:@[^\/@]+\/)?[^\/@]+)(?:@([^\/]+))?(\/.*)?$/
+
+function decodeParam(param) {
+  if (param) {
+    try {
+      return decodeURIComponent(param)
+    } catch (error) {
+      // Ignore invalid params.
+    }
+  }
+
+  return ''
+}
+
+function parsePackageURL(packageURL) {
+  const { pathname, search, query } = url.parse(packageURL, true)
+
+  const match = URLFormat.exec(pathname)
+
+  if (match == null)
+    return null
+
+  const packageName = match[1]
+  const packageVersion = decodeParam(match[2]) || 'latest'
+  const filename = decodeParam(match[3])
+
+  return {          // If the URL is /@scope/name@version/file.js?main=browser:
+    pathname,       // /@scope/name@version/path.js
+    search,         // ?main=browser
+    query,          // { main: 'browser' }
+    packageName,    // @scope/name
+    packageVersion, // version
+    filename        // /file.js
+  }
+}
+
+module.exports = parsePackageURL