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, 21 insertions, 9 deletions

diff --git a/build/tasks/build.js b/build/tasks/build.js
index e344f991b..61ec670fb 100644
--- a/build/tasks/build.js
+++ b/build/tasks/build.js
@@ -128,11 +128,11 @@ module.exports = function( grunt ) {
 			 * Adds the specified module to the excluded or included list, depending on the flag
 			 * @param {String} flag A module path relative to
 			 *  the src directory starting with + or - to indicate
-			 *  whether it should included or excluded
+			 *  whether it should be included or excluded
 			 */
 			const excluder = flag => {
 				let additional;
-				const m = /^(\+|\-|)([\w\/-]+)$/.exec( flag );
+				const m = /^(\+|-|)([\w\/-]+)$/.exec( flag );
 				const exclude = m[ 1 ] === "-";
 				const module = m[ 2 ];
 
@@ -150,10 +150,16 @@ module.exports = function( grunt ) {
 							// These are the removable dependencies
 							// It's fine if the directory is not there
 							try {
-								excludeList(
-									fs.readdirSync( `${ srcFolder }/${ module }` ),
-									module
-								);
+
+								// `selector` is a special case as we don't just remove
+								// the module, but we replace it with `selector-native`
+								// which re-uses parts of the `src/selector` folder.
+								if ( module !== "selector" ) {
+									excludeList(
+										fs.readdirSync( `${ srcFolder }/${ module }` ),
+										module
+									);
+								}
 							} catch ( e ) {
 								grunt.verbose.writeln( e );
 							}
@@ -232,14 +238,14 @@ module.exports = function( grunt ) {
 				// Remove the comma for anonymous defines
 				setOverride( `${ srcFolder }/exports/amd.js`,
 					read( "exports/amd.js" )
-						.replace( /(\s*)"jquery"(\,\s*)/,
+						.replace( /(\s*)"jquery"(,\s*)/,
 							amdName ? "$1\"" + amdName + "\"$2" : "" ) );
 			}
 
 			grunt.verbose.writeflags( excluded, "Excluded" );
 			grunt.verbose.writeflags( included, "Included" );
 
-			// Indicate a Slim build without listing all of the exclusions
+			// Indicate a Slim build without listing all the exclusions
 			// to save space.
 			if ( isPureSlim ) {
 				version += " slim";
@@ -260,7 +266,13 @@ module.exports = function( grunt ) {
 
 				// Replace excluded modules with empty sources.
 				for ( const module of excluded ) {
-					setOverride( `${ srcFolder }/${ module }.js`, "" );
+					setOverride(
+						`${ srcFolder }/${ module }.js`,
+
+						// The `selector` module is not removed, but replaced
+						// with `selector-native`.
+						module === "selector" ? read( "selector-native.js" ) : ""
+					);
 				}
 			}