allow naked binaryOp at the start of a selector within :has() (#145)

Co-authored-by: Richard Silverton <[email protected]>
Co-authored-by: Michael Ficarra <[email protected]>

README.md

@@ -19,7 +19,7 @@ The following selectors are supported:
 * [following sibling](http://dev.w3.org/csswg/selectors4/#general-sibling-combinators): `node ~ sibling`
 * [adjacent sibling](http://dev.w3.org/csswg/selectors4/#adjacent-sibling-combinators): `node + adjacent`
 * [negation](http://dev.w3.org/csswg/selectors4/#negation-pseudo): `:not(ForStatement)`
-* [has](https://drafts.csswg.org/selectors-4/#has-pseudo): `:has(ForStatement)`
+* [has](https://drafts.csswg.org/selectors-4/#has-pseudo): `:has(ForStatement)`, `:has(> ForStatement)`
 * [matches-any](http://dev.w3.org/csswg/selectors4/#matches): `:matches([attr] > :first-child, :last-child)`
 * [subject indicator](http://dev.w3.org/csswg/selectors4/#subject): `!IfStatement > [name="foo"]`
 * class of AST node: `:statement`, `:expression`, `:declaration`, `:function`, or `:pattern`

esquery.js

@@ -71,7 +71,11 @@ function inPath(node, ancestor, path, fromPathIndex) {
 
 /**
  * A generated matcher function for a selector.
- * @typedef {function} SelectorMatcher
+ * @callback SelectorMatcher
+ * @param {?SelectorAST} selector
+ * @param {external:AST[]} [ancestry=[]]
+ * @param {ESQueryOptions} [options]
+ * @returns {void}
 */
 
 /**
@@ -123,6 +127,11 @@ function generateMatcher(selector) {
             };
         }
 
+        case 'exactNode':
+            return (node, ancestry) => {
+                return ancestry.length === 0;
+            };
+
         case 'field': {
             const path = selector.name.split('.');
             return (node, ancestry) => {

grammar.pegjs

@@ -30,10 +30,21 @@ binaryOp
   / _ "+" _ { return 'adjacent'; }
   / " " _ { return 'descendant'; }
 
+hasSelectors = s:hasSelector ss:(_ "," _ hasSelector)* {
+  return [s].concat(ss.map(function (s) { return s[3]; }));
+}
+
 selectors = s:selector ss:(_ "," _ selector)* {
   return [s].concat(ss.map(function (s) { return s[3]; }));
 }
 
+
+hasSelector
+  = op:binaryOp? s:selector {
+    if (!op) return s;
+    return { type: op, left: { type: 'exactNode' }, right: s };
+  }
+
 selector
   = a:sequence ops:(binaryOp sequence)* {
     return ops.reduce(function (memo, rhs) {
@@ -96,7 +107,7 @@ field = "." i:identifierName is:("." identifierName)* {
 
 negation = ":not(" _ ss:selectors _ ")" { return { type: 'not', selectors: ss }; }
 matches = ":matches(" _ ss:selectors _ ")" { return { type: 'matches', selectors: ss }; }
-has = ":has(" _ ss:selectors _ ")" { return { type: 'has', selectors: ss }; }
+has = ":has(" _ ss:hasSelectors _ ")" { return { type: 'has', selectors: ss }; }
 
 firstChild = ":first-child" { return nth(1); }
 lastChild = ":last-child" { return nthLast(1); }