[fix] call custom predicate

lib/slideHelper.js

@@ -26,7 +26,7 @@ const startSliding = (k, predicate, host, guest, window, windowPos) => {
 
 	const test = predicate ?  predicate : isEq;
 
-	const firstMatch = host.findIndex(wrap(isEq, window[0]));
+	const firstMatch = host.findIndex(wrap(test, window[0]));
 
 	// If first item returns a match, then continue to slideNext()
 	const len = firstMatch ? slideNext(host, guest, firstMatch, windowPos) : undefined;

test.js

@@ -3,5 +3,5 @@ const Slider = require('.');
 const a = [ 0, 1, 2, 3, 4, 5 ];
 const b = [ 2, 3, 4 ];
 
-const w = new Slider({ size: 3 });
+const w = new Slider({ size: 3 , predicate: (a, b) => a === b });
 console.log(w.slide(a, b));