Summary

Backport jQuery selection context logic to selector-native.

This makes:

$div.find("div > *")

no longer matching children of $div.

Also, leading combinators now work, e.g.:

$div.find( "> *" );

returns children of $div.

As a result of that, a number of tests are no longer skipped in the selector-native mode.

Fixes gh-5185
Ref gh-5085

The full build is at +19 bytes now. I'm sure this can be reduced a bit but some may be unavoidable unless we want to duplicate a lot of code between selector & selector-native which I'd like to avoid.

The selector-native build is at -3274 bytes compared to the full main (c66d470) build and at +1056 bytes compared to the selector-native build on that same main build.

It's quite likely more size optimizations are possible in the selector-native build, I'd appreciate some ideas. One thing I know about is the tokenize & toSelector functions could be simplified slightly as it's enough to collect string parts without all the other context information - instead of:

tokens.push( {
	value: matched,
	type: type,
	matches: match
} );

it'd be enough to:

tokens.push( matched )

and toSelector would be simplified from:

function toSelector( tokens ) {
	var i = 0,
		len = tokens.length,
		selector = "";
	for ( ; i < len; i++ ) {
		selector += tokens[ i ].value;
	}
	return selector;
}

to:

function toSelector( tokens ) {
	return tokens.join( "" );
}

That would save 37 bytes in the selector-native build but would require duplicating those two functions and especially the tokenize one is quite large so I opted against that for now.

Checklist

• New tests have been added to show the fix or feature works
• Grunt build and unit tests pass locally with these changes
• If needed, a docs issue/PR was created at https://github.com/jquery/api.jquery.com