Check if string ' s ▁ length ▁ is ▁ ▁ less ▁ than ▁ pattern ' s length . If yes then no such window can exist
if ( len1 < len2 ) { document . write ( " " ) ; return " " ; } var hash_pat = Array . from ( { length : no_of_chars } , ( _ , i ) => 0 ) ; var hash_str = Array . from ( { length : no_of_chars } , ( _ , i ) => 0 ) ;