feat: add normalizers (byEngine and toDesktop)

README.md

@@ -515,10 +515,20 @@ Options:
   Default is `false.`
 * `dangerousExtend`: Disable security checks for `extend` query.
   Default is `false.`
-* `mobileToDesktop`: Use desktop browsers if Can I Use doesn’t have data
-  about this mobile version. For instance, Browserslist will return
-  `chrome 20` on `and_chr 20` query (Can I Use has only data only about
-  latest versions of mobile browsers). Default is `false`.
+* `mobileToDesktop`: Resolve the mobile version using the desktop version when
+  Can I Use doesn't have data about the specified version. For instance, it
+  will return two Chrome for Android versions even if Can I Use has only
+  data only about the latest version. Default is `false`.
+* `normalizers`: An array of names of normalizers below and functions
+  that accept a browser and return the normalized versions, which are
+  applied to resolved browsers in order. For instance, `['byEngine', 'toDesktop']`.
+  * `byEngine`: Normalize Chromium-based browsers to Chrome. For instance,
+    UC Browser, QQ Browser, Baidu browser for Android, and Samsung Internet
+    will return `and_chr` with the version of Chromium they are based on.
+    Note Edge and Opera is not normalized. Gecko-based browsers are
+    also normalized to Firefox, e.g., KaiOS Browser will return `and_ff`.
+  * `toDesktop`: Normalize mobile browsers to desktop browsers.
+    For instance, Browserslist will return `chrome 20` on `and_chr 20`
 
 For non-JS environment and debug purpose you can use CLI tool:
 

cli.js

@@ -19,6 +19,7 @@ var USAGE = 'Usage:\n' +
             '  npx browserslist --env="environment name defined in config"\n' +
             '  npx browserslist --stats="path/to/browserlist/stats/file"\n' +
             '  npx browserslist --mobile-to-desktop\n' +
+            '  npx browserslist --normalizers=byEngine,toDesktop\n' +
             '  npx browserslist --update-db'
 
 function isArg (arg) {
@@ -75,6 +76,8 @@ if (isArg('--help') || isArg('-h')) {
       mode = 'json'
     } else if (name === '--mobile-to-desktop') {
       opts.mobileToDesktop = true
+    } else if (name === '--normalizers') {
+      opts.normalizers = value.split(',')
     } else {
       error('Unknown arguments ' + args[i] + '.\n\n' + USAGE)
     }

index.js

@@ -9,6 +9,7 @@ var env = require('./node') // Will load browser.js in webpack
 
 var YEAR = 365.259641 * 24 * 60 * 60 * 1000
 var ANDROID_EVERGREEN_FIRST = 37
+var ANDROID_CLASSIC_REGEX = /^(?:[2-4]\.|[34]$)/
 
 var QUERY_OR = 1
 var QUERY_AND = 2
@@ -265,7 +266,7 @@ function normalizeAndroidVersions (androidVersions, chromeVersions) {
   var firstEvergreen = ANDROID_EVERGREEN_FIRST
   var last = chromeVersions[chromeVersions.length - 1]
   return androidVersions
-    .filter(function (version) { return /^(?:[2-4]\.|[34]$)/.test(version) })
+    .filter(function (version) { return ANDROID_CLASSIC_REGEX.test(version) })
     .concat(chromeVersions.slice(firstEvergreen - last - 1))
 }
 
@@ -315,7 +316,7 @@ function resolve (queries, context) {
     queries = parse(queries)
   }
 
-  return queries.reduce(function (result, query, index) {
+  var list = queries.reduce(function (result, query, index) {
     var selection = query.queryString
 
     var isExclude = selection.indexOf('not ') === 0
@@ -371,6 +372,18 @@ function resolve (queries, context) {
 
     throw unknownQuery(selection)
   }, [])
+
+  if (context.normalizers) {
+    list = context.normalizers.reduce(function (result, normalizer) {
+      normalizer = NORMALIZERS[normalizer] || normalizer
+      if (typeof normalizer !== 'function') {
+        throw new BrowserslistError('Unknown normalizer ' + normalizer)
+      }
+      return result.map(normalizer)
+    }, list)
+  }
+
+  return list
 }
 
 var cache = { }
@@ -395,6 +408,10 @@ var cache = { }
  * @param {boolean} [opts.mobileToDesktop] Alias mobile browsers to the desktop
  *                                         version when Can I Use doesn't have
  *                                         data about the specified version.
+ * @param {(string|function)[]} [opts.normalizers] An array of names of
+ *                                                 normalizers and functions
+ *                                                 that accept a browser and
+ *                                                 return normalized versions.
  * @returns {string[]} Array with browser names in Can I Use.
  *
  * @example
@@ -425,6 +442,7 @@ function browserslist (queries, opts) {
     ignoreUnknownVersions: opts.ignoreUnknownVersions,
     dangerousExtend: opts.dangerousExtend,
     mobileToDesktop: opts.mobileToDesktop,
+    normalizers: opts.normalizers,
     env: opts.env
   }
 
@@ -546,6 +564,46 @@ browserslist.desktopNames = {
   android: 'chrome' // has extra processing logic
 }
 
+// Tools such as compat-table only provides compatibility data for
+// popular browsers. Fallback to Chrome for Chromium-based browsers
+// and Firefox for Gecko-based browsers. A number indicates `and_chr`
+browserslist.normalizedVersions = {
+  // From Samsung Internet release notes at
+  // https://developer.samsung.com/internet/release-note.html,
+  // Chrome version page (chrome://version), and the user agent string
+  // Also available at https://github.com/mdn/browser-compat-data/blob/master
+  // /browsers/samsunginternet_android.json
+  'samsung 4': 44,
+  'samsung 5': 51,
+  'samsung 6': 56,
+  'samsung 7': 59,
+  'samsung 8': 63,
+  'samsung 9': 67,
+  'samsung 10': 71,
+  'samsung 11': 75,
+  'samsung 12': 79,
+
+  // From Opera for Android release notes at
+  // https://forums.opera.com/category/20/opera-for-android
+  // Opera version page (opera://version), and the user agent string
+  // Also available at https://github.com/mdn/browser-compat-data/blob/master
+  // /browsers/opera_android.json
+  'op_mob 46': 63,
+
+  // From the kernel version at https://plus.ucweb.com/download/
+  // and the user agent string
+  'and_uc 12': 57,
+
+  // From https://browser.qq.com/ and the user agent string
+  'and_qq 10': 70,
+
+  // From the user agent string
+  'baidu 7': 48,
+
+  // From https://github.com/kaiostech/gecko-b2g and the user agent string
+  'kaios 2': 'and_ff 48'
+}
+
 // Aliases to work with joined versions like `ios_saf 7.0-7.1`
 browserslist.versionAliases = { }
 
@@ -1141,7 +1199,30 @@ var QUERIES = [
       }
     }
   }
-];
+]
+
+var NORMALIZERS = {
+  byEngine: function (browser) {
+    var major = browser.split('.')[0]
+    var normalized = browserslist.normalizedVersions[major]
+    if (!normalized) {
+      return browser
+    } else if (typeof normalized === 'number') {
+      normalized = 'and_chr ' + normalized
+    }
+    return normalized
+  },
+  toDesktop: function (browser) {
+    browser = browser.split(' ')
+    var name = browser[0]
+    var version = browser[1]
+    if (browserslist.desktopNames[name] &&
+        !(name === 'android' && ANDROID_CLASSIC_REGEX.test(version))) {
+      name = browserslist.desktopNames[name]
+    }
+    return name + ' ' + version
+  }
+};
 
 // Get and convert Can I Use data
 

package.json

@@ -131,6 +131,7 @@
       "JSDoc",
       "jspm",
       "KaiOS",
+      "normalizers",
       "npm",
       "postcss",
       "QQ",

test/normalizer.test.js

@@ -0,0 +1,83 @@
+let browserslist = require('../')
+
+let originData = browserslist.data
+let originNormalizedVersions = browserslist.normalizedVersions
+
+beforeEach(() => {
+  browserslist.data = {
+    samsung: {
+      name: 'samsung',
+      released: ['4'],
+      versions: ['4']
+    },
+    kaios: {
+      name: 'kaios',
+      released: ['2.5'],
+      versions: ['2.5']
+    },
+    android: {
+      name: 'android',
+      released: ['4.4', '4.4.3-4.4.4', '37'],
+      versions: ['4.4', '4.4.3-4.4.4', '37']
+    },
+    and_chr: {
+      name: 'and_chr',
+      released: ['83'],
+      versions: ['83']
+    }
+  }
+
+  browserslist.normalizedVersions = {
+    'samsung 4': 44,
+    'kaios 2': 'and_ff 48'
+  }
+})
+
+afterEach(() => {
+  browserslist.data = originData
+  browserslist.normalizedVersions = originNormalizedVersions
+})
+
+it('normalizes mobile browsers to desktop browsers', () => {
+  let opts = { normalizers: ['toDesktop'] }
+  expect(browserslist('android 37', opts)).toEqual(['chrome 37'])
+  expect(browserslist('last 1 and_chr versions', opts)).toEqual(['chrome 83'])
+  expect(browserslist('samsung 4', opts)).toEqual(['samsung 4'])
+})
+
+it('does not normalize classic Android webview versions', () => {
+  let opts = { normalizers: ['toDesktop'] }
+  expect(browserslist('android 4.4-37', opts)).toEqual([
+    'android 4.4.3-4.4.4', 'android 4.4', 'chrome 37'
+  ])
+})
+
+it('normalizes Chromium-based browsers to Chrome', () => {
+  let opts = { normalizers: ['byEngine'] }
+  expect(browserslist('samsung 4', opts)).toEqual(['and_chr 44'])
+  expect(browserslist('kaios 2.5', opts)).toEqual(['and_ff 48'])
+  expect(browserslist('and_chr 83', opts)).toEqual(['and_chr 83'])
+})
+
+it('should apply each normalizer in order', () => {
+  let opts = { normalizers: ['byEngine', 'toDesktop'] }
+  expect(browserslist('samsung 4', opts)).toEqual(['chrome 44'])
+  expect(browserslist('kaios 2.5', opts)).toEqual(['firefox 48'])
+  expect(browserslist('and_chr 83', opts)).toEqual(['chrome 83'])
+})
+
+it('accepts a normalizer function', () => {
+  let opts = { normalizers: [() => 'samsung 4'] }
+  expect(browserslist('android 37', opts)).toEqual(['samsung 4'])
+})
+
+it('raises on unknown normalizer', () => {
+  let opts1 = { normalizers: ['_'] }
+  let opts2 = { normalizers: [{}] }
+  expect(() => {
+    browserslist('samsung 4', opts1)
+  }).toThrow('Unknown normalizer _')
+  expect(() => {
+    browserslist('samsung 4', opts2)
+  }).toThrow('Unknown normalizer [object Object]')
+})