6. 함수형 프로그래밍 - pipe

function reduce( $list, $fn, $memo )

{

let memo = $memo;

each( $list, ( $item ) => memo = $fn( memo, $item ));

return memo;

}

function each( $list, $fn ){

for( let item of $list ){

$fn( item );

}

}

function pipe()

{

let fns = arguments;

return ( arg ) => reduce( fns, ( arg, fn ) => fn( arg ), arg );

}

let f1 = pipe(

( a ) => a + 1,

( a ) => a + 2,

( a ) => a * a

);

console.log( f1( 1 ));

console.log( f1( 2 ));