Big Factorial Code

big-factorial.js

function bigFactorial( bigNumber ){
	return	(
				eval(
					Object
					.keys(
						Array(
							Math.floor( Math.sqrt( bigNumber ) )
						)
						.join( )
						.split( "," )
					)
					.map(
						( value ) => (
							BigInt( value ) + 1n
						)
					)
					.map(
						( pageIndexValue ) => (
							Object
							.keys(
								Array(
									Math.floor( bigNumber / Math.floor( Math.sqrt( bigNumber ) ) )
								)
								.join( )
								.split( "," )
							)
							.map(
								( value ) => (
										( BigInt( value ) + 1n )
									+	(
												BigInt( Math.floor( bigNumber / Math.floor( Math.sqrt( bigNumber ) ) ) )
											*	( pageIndexValue - 1n )
										)
								)
							)
						)
					)
					.concat(
						[
							Object
							.keys(
								Array(
										bigNumber
									-	(
												Math.floor( Math.sqrt( bigNumber ) )
											*	Math.floor( bigNumber / Math.floor( Math.sqrt( bigNumber ) ) )
										)
								)
								.join( )
								.split( "," )
							)
							.slice(
								Number(
										(
												bigNumber
											-	(
														Math.floor( Math.sqrt( bigNumber ) )
													*	Math.floor( bigNumber / Math.floor( Math.sqrt( bigNumber ) ) )
												)
										)
									===	0
								)
							)
							.map(
								( value ) => (
										( BigInt( value ) + 1n )
									+	(
												BigInt( Math.floor( Math.sqrt( bigNumber ) ) )
											*	BigInt( Math.floor( bigNumber / Math.floor( Math.sqrt( bigNumber ) ) ) )
										)
								)
							)
						]
					)
					.filter( 
						( list ) => ( 
							list.length > 0 
						) 
					)
					.map( 
						( list ) => (
							eval( 
								list
								.join( "*" )
								.replace( /(\d+)/g, "$1n" ) 
							)
						)
					)
					.join("*")
					.replace( /(\d+)/g, "$1n" )
				)
			);
}