chore: add tests

Author: ascorbic

demos/middleware/next.config.js

@@ -7,6 +7,10 @@ const nextConfig = {
     ignoreDuringBuilds: true,
   },
   generateBuildId: () => 'build-id',
+  i18n: {
+    defaultLocale: 'en',
+    locales: ['en'],
+  },
 }
 
 module.exports = nextConfig

package-lock.json

@@ -25,7 +25,7 @@ export const stripLookahead = (regex: string) => {
 }
 
 const LOCALIZED_REGEX_PREFIX = '(?:\\/(_next\\/data\\/[^/]{1,}))?(?:\\/([^/.]{1,}))'
-const OPTIONAL_REGEX_PREFIX = '(?:\\/(_next\\/data\\/[^/]{1,}))?(?:\\/([^/.]*))'
+const OPTIONAL_REGEX_PREFIX = '(?:\\/(_next\\/data\\/[^/]{1,}))?(?:\\/([^/.]{1,}))?'
 
 // Make the locale section of the matcher regex optional
 export const makeLocaleOptional = (regex: string) => regex.replace(LOCALIZED_REGEX_PREFIX, OPTIONAL_REGEX_PREFIX)

packages/runtime/src/helpers/matchers.ts

@@ -0,0 +1,72 @@
+import { makeLocaleOptional, stripLookahead } from '../packages/runtime/src/helpers/matchers'
+
+const makeDataPath = (path: string) => `/_next/data/build-id${path === '/' ? '/index' : path}.json`
+
+function checkPath(path: string, regex: string) {
+  const re = new RegExp(regex)
+  const dataPath = makeDataPath(path)
+  const testPath = re.test(path)
+  const testData = re.test(dataPath)
+  //   For easier debugging
+  //   console.log({ path, regex, dataPath, testPath, testData })
+  return testPath && testData
+}
+
+describe('the middleware path matcher', () => {
+  it('makes the locale slug optional in the regex for the root', () => {
+    // The regex generated by Next for the path "/" with i18n enabled
+    const regex =
+      '^(?:\\/(_next\\/data\\/[^/]{1,}))?(?:\\/([^/.]{1,}))(|\\.json|\\/?index|\\/?index\\.json)?[\\/#\\?]?$'
+    expect(checkPath('/', regex)).toBe(false)
+    expect(checkPath('/', makeLocaleOptional(regex))).toBe(true)
+    expect(checkPath('/en', makeLocaleOptional(regex))).toBe(true)
+  })
+
+  it('makes the locale slug optional in the regex for a subpath', () => {
+    // The regex generated by Next for the path "/static" with i18n enabled
+    const regex = '^(?:\\/(_next\\/data\\/[^/]{1,}))?(?:\\/([^/.]{1,}))\\/static(.json)?[\\/#\\?]?$'
+    expect(checkPath('/static', regex)).toBe(false)
+    expect(checkPath('/static', makeLocaleOptional(regex))).toBe(true)
+    expect(checkPath('/en/static', makeLocaleOptional(regex))).toBe(true)
+  })
+
+  it('does not change the regex when calling makeLocaleOptional with a regex that has no locale', () => {
+    const regexes = [
+      '^(?:\\/(_next\\/data\\/[^/]{1,}))?(?:\\/(\\/?index|\\/?index\\.json))?[\\/#\\?]?$',
+      '^(?:\\/(_next\\/data\\/[^/]{1,}))?\\/api(?:\\/((?:[^\\/#\\?]+?)(?:\\/(?:[^\\/#\\?]+?))*))?(.json)?[\\/#\\?]?$',
+      '^(?:\\/(_next\\/data\\/[^/]{1,}))?\\/shows(?:\\/((?!99|88).*))(.json)?[\\/#\\?]?$',
+    ]
+    for (const regex of regexes) {
+      expect(makeLocaleOptional(regex)).toBe(regex)
+    }
+  })
+
+  it('removes lookaheads from the regex', () => {
+    const regexes = [
+      '^(?:\\/(_next\\/data\\/[^/]{1,}))?(?:\\/([^/.]{1,}))\\/shows(?:\\/((?!99|88).*))(.json)?[\\/#\\?]?$',
+      '^(?:\\/(_next\\/data\\/[^/]{1,}))?\\/shows(?:\\/((?!99|88).*))(.json)?[\\/#\\?]?$',
+    ]
+    for (const regex of regexes) {
+      const stripped = stripLookahead(regex)
+      expect(regex).toMatch(/\(\?!/)
+      expect(stripped).not.toMatch(/\(\?!/)
+    }
+  })
+  it('converts regexes with lookaheads to stripped ones that still match at least the same paths', () => {
+    const regex = '^(?:\\/(_next\\/data\\/[^/]{1,}))?\\/shows(?:\\/((?!99|88).*))(.json)?[\\/#\\?]?$'
+    expect(checkPath('/shows', regex)).toBe(false)
+    expect(checkPath('/shows/11', regex)).toBe(true)
+    expect(checkPath('/shows/99', regex)).toBe(false)
+    expect(checkPath('/shows/888', regex)).toBe(false)
+
+    const stripped = stripLookahead(regex)
+    expect(checkPath('/shows', stripped)).toBe(false)
+    expect(checkPath('/shows/11', stripped)).toBe(true)
+    // These will be true because the regex is not as strict as the original one
+    // The strict test will be done in the JS entrypoint
+    expect(checkPath('/shows/99', stripped)).toBe(true)
+    expect(checkPath('/shows/888', stripped)).toBe(true)
+  })
+})
+
+// "regexp": "^(?:\\/(_next\\/data\\/[^/]{1,}))?(?:\\/([^/.]{1,}))\\/shows(?:\\/((?!99|88).*))(.json)?[\\/#\\?]?$"