Re-organize package URL parsing

server/utils/createPackageURL.js

@@ -0,0 +1,16 @@
+function createPackageURL(packageName, version, filename, search) {
+  let pathname = `/${packageName}`
+
+  if (version != null)
+    pathname += `@${version}`
+
+  if (filename)
+    pathname += filename
+
+  if (search)
+    pathname += search
+
+  return pathname
+}
+
+module.exports = createPackageURL

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

server/utils/parsePackageURL.test.js

@@ -0,0 +1,84 @@
+const parsePackageURL = require('./parsePackageURL')
+
+describe('parsePackageURL', () => {
+  it('parses plain packages', () => {
+    expect(parsePackageURL('/history@1.0.0/umd/history.min.js')).toEqual({
+      pathname: '/history@1.0.0/umd/history.min.js',
+      search: '',
+      query: {},
+      packageName: 'history',
+      packageVersion: '1.0.0',
+      filename: '/umd/history.min.js'
+    })
+  })
+
+  it('parses plain packages with a hyphen in the name', () => {
+    expect(parsePackageURL('/query-string@5.0.0/index.js')).toEqual({
+      pathname: '/query-string@5.0.0/index.js',
+      search: '',
+      query: {},
+      packageName: 'query-string',
+      packageVersion: '5.0.0',
+      filename: '/index.js'
+    })
+  })
+
+  it('parses plain packages with no version specified', () => {
+    expect(parsePackageURL('/query-string/index.js')).toEqual({
+      pathname: '/query-string/index.js',
+      search: '',
+      query: {},
+      packageName: 'query-string',
+      packageVersion: 'latest',
+      filename: '/index.js'
+    })
+  })
+
+  it('parses plain packages with version spec', () => {
+    expect(parsePackageURL('/query-string@>=4.0.0/index.js')).toEqual({
+      pathname: '/query-string@>=4.0.0/index.js',
+      search: '',
+      query: {},
+      packageName: 'query-string',
+      packageVersion: '>=4.0.0',
+      filename: '/index.js'
+    })
+  })
+
+  it('parses scoped packages', () => {
+    expect(parsePackageURL('/@angular/router@4.3.3/src/index.d.ts')).toEqual({
+      pathname: '/@angular/router@4.3.3/src/index.d.ts',
+      search: '',
+      query: {},
+      packageName: '@angular/router',
+      packageVersion: '4.3.3',
+      filename: '/src/index.d.ts'
+    })
+  })
+
+  it('parses package names with a period in them', () => {
+    expect(parsePackageURL('/index.js')).toEqual({
+      pathname: '/index.js',
+      search: '',
+      query: {},
+      packageName: 'index.js',
+      packageVersion: 'latest',
+      filename: ''
+    })
+  })
+
+  it('parses valid query parameters', () => {
+    expect(parsePackageURL('/history?main=browser')).toEqual({
+      pathname: '/history',
+      search: '?main=browser',
+      query: { main: 'browser' },
+      packageName: 'history',
+      packageVersion: 'latest',
+      filename: ''
+    })
+  })
+
+  it('returns null for invalid pathnames', () => {
+    expect(parsePackageURL('history')).toBe(null)
+  })
+})