const pipe = (...fns ) =>
  fns.reduce( ( f, g ) => (...args ) => g( f(...args ) ) )

const fx1 = ( x ) => ( before = 0 ) => before + x
const fx2 = ( x ) => ( before = 0 ) => before + ( x * x )
const fx3 = ( x ) => ( before = 0 ) => before + ( x * x * x )

// f(x) = x^3 + x^2 + x
const result = ( x ) => pipe( fx3( x ), fx2( x ), fx1( x ) )()

console.log( result( 2 ) )
// 14