Add support for a:has(> b)

lib/walk.js

@@ -44,7 +44,7 @@ const empty = []
  */
 export function walk(state, tree) {
   if (tree) {
-    one(state, [], tree, undefined, undefined)
+    one(state, [], tree, undefined, undefined, tree)
   }
 }
 
@@ -76,10 +76,12 @@ function add(nest, field, rule) {
  *   Nesting.
  * @param {Parents} node
  *   Parent.
+ * @param {Nodes} tree
+ *   Tree.
  * @returns {undefined}
  *   Nothing.
  */
-function all(state, nest, node) {
+function all(state, nest, node, tree) {
   const fromParent = combine(nest.descendant, nest.directChild)
   /** @type {Array<AstRule> | undefined} */
   let fromSibling
@@ -118,7 +120,14 @@ function all(state, nest, node) {
     // for parents so that we delve into custom nodes too.
     if ('children' in child) {
       const forSibling = combine(fromParent, fromSibling)
-      const nest = one(state, forSibling, node.children[index], index, node)
+      const nest = one(
+        state,
+        forSibling,
+        node.children[index],
+        index,
+        node,
+        tree
+      )
       fromSibling = combine(nest.generalSibling, nest.adjacentSibling)
     }
 
@@ -268,10 +277,12 @@ function count(counts, node) {
  *   Index of `node` in `parent`.
  * @param {Parents | undefined} parent
  *   Parent of `node`.
+ * @param {Nodes} tree
+ *   Tree.
  * @returns {Nest}
  *   Nesting.
  */
-function one(state, currentRules, node, index, parent) {
+function one(state, currentRules, node, index, parent, tree) {
   /** @type {Nest} */
   let nestResult = {
     adjacentSibling: undefined,
@@ -283,10 +294,23 @@ function one(state, currentRules, node, index, parent) {
   const exit = enterState(state, node)
 
   if (node.type === 'element') {
+    let rootRules = state.rootQuery.rules
+
+    // Remove direct child rules if this is the root.
+    // This only happens for a `:has()` rule, which can be like
+    // `a:has(> b)`.
+    if (parent && parent !== tree) {
+      rootRules = state.rootQuery.rules.filter(
+        (d) =>
+          d.combinator === undefined ||
+          (d.combinator === '>' && parent === tree)
+      )
+    }
+
     nestResult = applySelectors(
       state,
       // Try the root rules for this element too.
-      combine(currentRules, state.rootQuery.rules),
+      combine(currentRules, rootRules),
       node,
       index,
       parent
@@ -296,7 +320,7 @@ function one(state, currentRules, node, index, parent) {
   // If this is a parent, and we want to delve into them, and we haven’t found
   // our single result yet.
   if ('children' in node && !state.shallow && !(state.one && state.found)) {
-    all(state, nestResult, node)
+    all(state, nestResult, node, tree)
   }
 
   exit()

readme.md

@@ -276,7 +276,7 @@ type Space = 'html' | 'svg'
 *   [x] `[attr$=value]` (attribute ends with)
 *   [x] `[attr*=value]` (attribute contains)
 *   [x] `:dir()` (functional pseudo-class)
-*   [x] `:has()` (functional pseudo-class)
+*   [x] `:has()` (functional pseudo-class; also supports `a:has(> b)`)
 *   [x] `:is()` (functional pseudo-class)
 *   [x] `:lang()` (functional pseudo-class)
 *   [x] `:not()` (functional pseudo-class)
@@ -313,8 +313,6 @@ type Space = 'html' | 'svg'
 *   [ ] ‡ `[*|attr]` (any namespace attribute)
 *   [ ] ‡ `[|attr]` (no namespace attribute)
 *   [ ] ‡ `[attr=value i]` (attribute case-insensitive)
-*   [ ] ‡ `:has()` (functional pseudo-class, note: relative selectors such as
-    `:has(> img)` are not supported, but scope is: `:has(:scope > img)`)
 *   [ ] ‖ `:nth-child(n of S)` (functional pseudo-class, note: scoping to
     parents is not supported)
 *   [ ] ‖ `:nth-last-child(n of S)` (functional pseudo-class, note: scoping to
@@ -362,8 +360,7 @@ type Space = 'html' | 'svg'
 *   ‡ — not supported by the underlying algorithm
 *   § — not very interested in writing / including the code for this
 *   ‖ — too new, the spec is still changing
-
-`:any()` and `:matches()` are renamed to `:is()` in CSS.
+*   `:any()` and `:matches()` are renamed to `:is()` in CSS.
 
 ## Types
 

test/matches.js

@@ -1346,31 +1346,28 @@ test('select.matches()', async function (t) {
         assert.ok(matches('a:has( img  ,\t p )', h('a', h('img'))))
       })
 
-      // To do: add `:has(>)`.
-      // Note: These should be uncommented, but that’s not supported by the CSS
-      // parser:
-      // await t.test(
-      //   'should match for relative direct child selector',
-      //   async function () {
-      //     assert.ok(matches('a:has(> img)', h('a', h('img'))))
-      //   }
-      // )
-
-      // await t.test(
-      //   'should not match for relative direct child selectors',
-      //   async function () {
-      //     assert.ok(!matches('a:has(> img)', h('a', h('span', h('img')))))
-      //   }
-      // )
-
-      // await t.test(
-      //   'should support a list of relative selectors',
-      //   async function () {
-      //     assert.ok(
-      //       matches('a:has(> img, > span)', h('a', h('span', h('span'))))
-      //     )
-      //   }
-      // )
+      await t.test(
+        'should match for relative direct child selector',
+        async function () {
+          assert.ok(matches('a:has(> img)', h('a', h('img'))))
+        }
+      )
+
+      await t.test(
+        'should not match for relative direct child selectors',
+        async function () {
+          assert.ok(!matches('a:has(> img)', h('a', h('span', h('img')))))
+        }
+      )
+
+      await t.test(
+        'should support a list of relative selectors',
+        async function () {
+          assert.ok(
+            matches('a:has(> img, > span)', h('a', h('span', h('span'))))
+          )
+        }
+      )
     })
 
     await t.test(':any-link', async function (t) {