fix(find): Make it possible to find siblings (#1583)

Fixes #1244
Fixes #1095

lib/api/traversing.js

@@ -9,6 +9,7 @@ var utils = require('../utils');
 var domEach = utils.domEach;
 var uniqueSort = require('htmlparser2').DomUtils.uniqueSort;
 var isTag = utils.isTag;
+var reSiblingSelector = /^\s*[~+]/;
 
 /**
  * Get the descendants of each element in the current set of matched elements,
@@ -26,9 +27,6 @@ var isTag = utils.isTag;
  * @see {@link http://api.jquery.com/find/}
  */
 exports.find = function (selectorOrHaystack) {
-  var elems = this.toArray().reduce(function (newElems, elem) {
-    return newElems.concat(elem.children.filter(isTag));
-  }, []);
   var contains = this.constructor.contains;
   var haystack;
 
@@ -52,9 +50,20 @@ exports.find = function (selectorOrHaystack) {
     );
   }
 
-  var options = { __proto__: this.options, context: this.toArray() };
+  if (!selectorOrHaystack) {
+    return this._make([]);
+  }
+
+  var context = this.toArray();
+  var elems = reSiblingSelector.test(selectorOrHaystack)
+    ? context
+    : context.reduce(function (newElems, elem) {
+        return newElems.concat(elem.children.filter(isTag));
+      }, []);
+
+  var options = Object.assign({ context: context }, this.options);
 
-  return this._make(select.select(selectorOrHaystack || '', elems, options));
+  return this._make(select.select(selectorOrHaystack, elems, options));
 };
 
 /**

test/api/traversing.js

@@ -61,6 +61,15 @@ describe('$(...)', function () {
       expect(q('foo').find('> bar')).to.have.length(1);
     });
 
+    it('should find siblings', function () {
+      var q = cheerio.load('<p class=a><p class=b></p>');
+      expect(q('.a').find('+.b')).to.have.length(1);
+      expect(q('.a').find('~.b')).to.have.length(1);
+      // Should not find itself
+      expect(q('.a').find('+.a')).to.have.length(0);
+      expect(q('.a').find('~.a')).to.have.length(0);
+    });
+
     it('should query case-sensitively when in xml mode', function () {
       var q = cheerio.load('<caseSenSitive allTheWay>', { xml: true });
       expect(q('caseSenSitive')).to.have.length(1);