Selector: Re-introduce selector-native.js

Re-introduce the `selector-native` similar to the one on the `3.x-stable`
branch. One difference is since the `main` branch inlined Sizzle, some
selector utils can be shared between the main `selector` module and
`selector-native`.

The main `selector` module can be disabled in favor of `selector-native`
via:

    grunt custom:-selector

Other changes:
* Tests: Fix Safari detection - Chrome Headless has a different user
  agent than Safari and a browser check in selector tests didn't take
  that into account.
* Tests: Run selector-native tests in `npm test`
* Selector: Fix querying on document fragments

Ref gh-4395
Closes gh-5085

1 files changed, 88 insertions, 0 deletions

diff --git a/src/selector-native.js b/src/selector-native.js
new file mode 100644
index 000000000..0e2e48d81
--- /dev/null
+++ b/src/selector-native.js
@@ -0,0 +1,88 @@
+/*
+ * Optional limited selector module for custom builds.
+ *
+ * Note that this DOES NOT SUPPORT many documented jQuery
+ * features in exchange for its smaller size:
+ *
+ * * Attribute not equal selector (!=)
+ * * Positional selectors (:first; :eq(n); :odd; etc.)
+ * * Type selectors (:input; :checkbox; :button; etc.)
+ * * State-based selectors (:animated; :visible; :hidden; etc.)
+ * * :has(selector)
+ * * :not(complex selector)
+ * * custom selectors via jQuery extensions
+ * * Leading combinators (e.g., $collection.find("> *"))
+ * * Reliable functionality on XML fragments
+ * * Requiring all parts of a selector to match elements under context
+ *     (e.g., $div.find("div > *") now matches children of $div)
+ * * Matching against non-elements
+ * * Reliable sorting of disconnected nodes
+ * * querySelectorAll bug fixes (e.g., unreliable :focus on WebKit)
+ *
+ * If any of these are unacceptable tradeoffs, either use the full
+ * selector engine or  customize this stub for the project's specific
+ * needs.
+ */
+
+import jQuery from "./core.js";
+import document from "./var/document.js";
+import documentElement from "./var/documentElement.js";
+import whitespace from "./var/whitespace.js";
+
+// The following utils are attached directly to the jQuery object.
+import "./selector/contains.js";
+import "./selector/escapeSelector.js";
+import "./selector/uniqueSort.js";
+
+// Support: IE 9 - 11+
+// IE requires a prefix.
+var matches = documentElement.matches || documentElement.msMatchesSelector;
+
+jQuery.extend( {
+	find: function( selector, context, results, seed ) {
+		var elem, nodeType,
+			i = 0;
+
+		results = results || [];
+		context = context || document;
+
+		// Same basic safeguard as in the full selector module
+		if ( !selector || typeof selector !== "string" ) {
+			return results;
+		}
+
+		// Early return if context is not an element, document or document fragment
+		if ( ( nodeType = context.nodeType ) !== 1 && nodeType !== 9 && nodeType !== 11 ) {
+			return [];
+		}
+
+		if ( seed ) {
+			while ( ( elem = seed[ i++ ] ) ) {
+				if ( jQuery.find.matchesSelector( elem, selector ) ) {
+					results.push( elem );
+				}
+			}
+		} else {
+			jQuery.merge( results, context.querySelectorAll( selector ) );
+		}
+
+		return results;
+	},
+	expr: {
+		attrHandle: {},
+		match: {
+			bool: new RegExp( "^(?:checked|selected|async|autofocus|autoplay|controls|defer" +
+				"|disabled|hidden|ismap|loop|multiple|open|readonly|required|scoped)$", "i" ),
+			needsContext: new RegExp( "^" + whitespace + "*[>+~]" )
+		}
+	}
+} );
+
+jQuery.extend( jQuery.find, {
+	matches: function( expr, elements ) {
+		return jQuery.find( expr, null, null, elements );
+	},
+	matchesSelector: function( elem, expr ) {
+		return matches.call( elem, expr );
+	}
+} );