add support for analyzing pseudo-classes (#433)

closes #432

Author: bartveneman

src/__fixtures__/bol-com-20231008.json

@@ -54964,6 +54964,39 @@
       "uniquenessRatio": 0,
       "ratio": 0
     },
+    "pseudoClasses": {
+      "total": 2010,
+      "totalUnique": 26,
+      "unique": {
+        "not": 167,
+        "root": 3,
+        "-moz-focusring": 8,
+        "focus": 94,
+        "focus-visible": 66,
+        "first-child": 57,
+        "after": 447,
+        "before": 586,
+        "hover": 280,
+        "active": 131,
+        "has": 2,
+        "last-child": 45,
+        "checked": 35,
+        "focus-within": 13,
+        "empty": 1,
+        "-moz-placeholder": 3,
+        "-ms-input-placeholder": 3,
+        "last-of-type": 5,
+        "nth-of-type": 11,
+        "first-of-type": 2,
+        "nth-child": 4,
+        "disabled": 34,
+        "placeholder-shown": 6,
+        "only-child": 2,
+        "indeterminate": 3,
+        "first-letter": 2
+      },
+      "uniquenessRatio": 0.012935323383084577
+    },
     "accessibility": {
       "total": 2,
       "totalUnique": 2,

src/__fixtures__/bootstrap-5.3.2.json

@@ -25889,6 +25889,37 @@
       "uniquenessRatio": 0,
       "ratio": 0
     },
+    "pseudoClasses": {
+      "total": 467,
+      "totalUnique": 24,
+      "unique": {
+        "root": 3,
+        "hover": 47,
+        "not": 145,
+        "focus": 66,
+        "focus-visible": 11,
+        "disabled": 27,
+        "last-child": 34,
+        "first-child": 36,
+        "nth-of-type": 1,
+        "nth-child": 2,
+        "-moz-focusring": 1,
+        "active": 11,
+        "checked": 13,
+        "indeterminate": 1,
+        "-moz-placeholder-shown": 4,
+        "placeholder-shown": 4,
+        "-webkit-autofill": 3,
+        "focus-within": 7,
+        "nth-last-child": 5,
+        "valid": 17,
+        "invalid": 17,
+        "empty": 6,
+        "first-of-type": 3,
+        "last-of-type": 3
+      },
+      "uniquenessRatio": 0.05139186295503212
+    },
     "accessibility": {
       "total": 1,
       "totalUnique": 1,

src/__fixtures__/cnn-20231008.json

@@ -31271,6 +31271,33 @@
       "uniquenessRatio": 1,
       "ratio": 0.0004955401387512388
     },
+    "pseudoClasses": {
+      "total": 2476,
+      "totalUnique": 20,
+      "unique": {
+        "root": 6,
+        "hover": 301,
+        "after": 113,
+        "not": 1363,
+        "last-child": 67,
+        "has": 76,
+        "first-child": 178,
+        "nth-child": 107,
+        "before": 127,
+        "active": 34,
+        "focus": 49,
+        "empty": 10,
+        "only-child": 9,
+        "is": 1,
+        "first-of-type": 13,
+        "last-of-type": 6,
+        "-ms-input-placeholder": 2,
+        "checked": 10,
+        "disabled": 2,
+        "nth-of-type": 2
+      },
+      "uniquenessRatio": 0.008077544426494346
+    },
     "accessibility": {
       "total": 4,
       "totalUnique": 4,

src/__fixtures__/css-tricks-20231008.json

@@ -12512,6 +12512,31 @@
       "uniquenessRatio": 0.8913043478260869,
       "ratio": 0.030223390275952694
     },
+    "pseudoClasses": {
+      "total": 386,
+      "totalUnique": 18,
+      "unique": {
+        "after": 19,
+        "before": 75,
+        "not": 130,
+        "nth-child": 2,
+        "first-child": 12,
+        "last-child": 17,
+        "focus": 47,
+        "hover": 46,
+        "is": 2,
+        "target": 6,
+        "first-of-type": 8,
+        "empty": 1,
+        "first-letter": 1,
+        "nth-of-type": 1,
+        "focus-within": 3,
+        "active": 2,
+        "root": 2,
+        "where": 12
+      },
+      "uniquenessRatio": 0.046632124352331605
+    },
     "accessibility": {
       "total": 2,
       "totalUnique": 2,

src/__fixtures__/gazelle-20231008.json

@@ -87405,6 +87405,37 @@
       "uniquenessRatio": 0.8229508196721311,
       "ratio": 0.05726086548390125
     },
+    "pseudoClasses": {
+      "total": 2883,
+      "totalUnique": 24,
+      "unique": {
+        "not": 269,
+        "active": 128,
+        "hover": 437,
+        "root": 2,
+        "after": 275,
+        "before": 821,
+        "visited": 6,
+        "focus": 278,
+        "last-child": 208,
+        "first-child": 220,
+        "nth-of-type": 7,
+        "-ms-input-placeholder": 1,
+        "empty": 4,
+        "link": 5,
+        "last-of-type": 39,
+        "first-of-type": 46,
+        "checked": 58,
+        "disabled": 34,
+        "nth-child": 35,
+        "first-letter": 1,
+        "has": 6,
+        "where": 1,
+        "-moz-focusring": 1,
+        "-moz-ui-invalid": 1
+      },
+      "uniquenessRatio": 0.008324661810613945
+    },
     "accessibility": {
       "total": 16,
       "totalUnique": 13,

src/__fixtures__/github-20231008.json

@@ -91789,6 +91789,46 @@
       "uniquenessRatio": 1,
       "ratio": 0.0011177347242921013
     },
+    "pseudoClasses": {
+      "total": 1942,
+      "totalUnique": 33,
+      "unique": {
+        "root": 65,
+        "not": 344,
+        "hover": 484,
+        "focus": 252,
+        "focus-visible": 112,
+        "disabled": 57,
+        "only-child": 6,
+        "active": 107,
+        "first-child": 91,
+        "last-child": 87,
+        "checked": 22,
+        "focus-within": 11,
+        "first-of-type": 14,
+        "last-of-type": 14,
+        "nth-child": 10,
+        "nth-last-child": 1,
+        "target": 16,
+        "empty": 13,
+        "is": 4,
+        "popover-open": 1,
+        "before": 113,
+        "after": 71,
+        "indeterminate": 1,
+        "nth-of-type": 30,
+        "has": 2,
+        "placeholder-shown": 3,
+        "placeholder": 1,
+        "dir": 2,
+        "defined": 1,
+        "-webkit-autofill": 2,
+        "invalid": 2,
+        "nth-last-of-type": 1,
+        "visited": 2
+      },
+      "uniquenessRatio": 0.016992790937178166
+    },
     "accessibility": {
       "total": 331,
       "totalUnique": 317,

src/__fixtures__/indiatimes-20231008.json

@@ -56553,6 +56553,29 @@
       "uniquenessRatio": 0.90625,
       "ratio": 0.003918207420105302
     },
+    "pseudoClasses": {
+      "total": 1081,
+      "totalUnique": 16,
+      "unique": {
+        "first-of-type": 13,
+        "after": 108,
+        "last-child": 255,
+        "checked": 3,
+        "first-child": 20,
+        "before": 294,
+        "last-of-type": 40,
+        "focus": 8,
+        "not": 110,
+        "hover": 103,
+        "nth-child": 119,
+        "nth-last-child": 3,
+        "active": 1,
+        "empty": 2,
+        "root": 1,
+        "Georgia": 1
+      },
+      "uniquenessRatio": 0.014801110083256245
+    },
     "accessibility": {
       "total": 0,
       "totalUnique": 0,

src/__fixtures__/smashing-magazine-20231008.json

@@ -48874,6 +48874,40 @@
       "uniquenessRatio": 0.875,
       "ratio": 0.0027590963959303327
     },
+    "pseudoClasses": {
+      "total": 1259,
+      "totalUnique": 27,
+      "unique": {
+        "not": 306,
+        "before": 83,
+        "after": 82,
+        "root": 3,
+        "-moz-focusring": 11,
+        "nth-of-type": 28,
+        "last-child": 25,
+        "active": 127,
+        "focus": 178,
+        "hover": 191,
+        "first-of-type": 21,
+        "nth-child": 49,
+        "-moz-placeholder": 2,
+        "-ms-input-placeholder": 10,
+        "target": 11,
+        "empty": 7,
+        "vertical": 1,
+        "horizontal": 1,
+        "first-child": 48,
+        "last-of-type": 20,
+        "-webkit-autofill": 29,
+        "checked": 12,
+        "nth-last-child": 4,
+        "visited": 1,
+        "-moz-placeholder-shown": 4,
+        "placeholder-shown": 4,
+        "first-line": 1
+      },
+      "uniquenessRatio": 0.021445591739475776
+    },
     "accessibility": {
       "total": 29,
       "totalUnique": 29,

src/__fixtures__/trello-20231008.json

@@ -10428,6 +10428,27 @@
       "uniquenessRatio": 1,
       "ratio": 0.003469210754553339
     },
+    "pseudoClasses": {
+      "total": 493,
+      "totalUnique": 14,
+      "unique": {
+        "hover": 85,
+        "focus": 120,
+        "not": 44,
+        "focus-visible": 40,
+        "disabled": 4,
+        "root": 1,
+        "last-child": 170,
+        "active": 17,
+        "last-of-type": 2,
+        "nth-child": 3,
+        "-ms-input-placeholder": 2,
+        "after": 1,
+        "before": 1,
+        "first-child": 3
+      },
+      "uniquenessRatio": 0.028397565922920892
+    },
     "accessibility": {
       "total": 0,
       "totalUnique": 0,

src/index.js

@@ -2,7 +2,7 @@ import parse from 'css-tree/parser'
 import walk from 'css-tree/walker'
 import { calculate } from '@bramus/specificity/core'
 import { isSupportsBrowserhack, isMediaBrowserhack } from './atrules/atrules.js'
-import { getCombinators, getComplexity, isAccessibility, isPrefixed } from './selectors/utils.js'
+import { getCombinators, getComplexity, isAccessibility, isPrefixed, hasPseudoClass } from './selectors/utils.js'
 import { colorFunctions, colorKeywords, namedColors, systemColors } from './values/colors.js'
 import { destructure, isSystemFont } from './values/destructure-font-shorthand.js'
 import { isValueKeyword, keywords } from './values/values.js'
@@ -156,6 +156,7 @@ export function analyze(css, options = {}) {
   let specificities = []
   let ids = new Collection(useLocations)
   let a11y = new Collection(useLocations)
+  let pseudoClasses = new Collection(useLocations)
   let combinators = new Collection(useLocations)
 
   // Declarations
@@ -307,6 +308,13 @@ export function analyze(css, options = {}) {
           a11y.p(selector, node.loc)
         }
 
+        let pseudos = hasPseudoClass(node)
+        if (pseudos !== false) {
+          for (let pseudo of pseudos) {
+            pseudoClasses.p(pseudo, node.loc)
+          }
+        }
+
         let complexity = getComplexity(node)
 
         if (isPrefixed(node)) {
@@ -820,6 +828,7 @@ export function analyze(css, options = {}) {
         ids.c(), {
         ratio: ratio(ids.size(), totalSelectors),
       }),
+      pseudoClasses: pseudoClasses.c(),
       accessibility: assign(
         a11y.c(), {
         ratio: ratio(a11y.size(), totalSelectors),