Hi good people!

Why not using factory functions to achieve the same thing that decorators do?

Look at my code to achieve your same Batman example:

const comicBookCharacter = ( first, last ) => {
  const firstName = first
  const lastName = last
  return {
    realName: `${firstName} ${lastName}`
  }
}
const superPower = ( ref ) => {
  let powers = []
  return {
    addPower: ( p ) => {
      powers.push( p )
      return ref
    },
    powers
  }
}
const utilityBelt = ( ref ) => {
  let utilities = []
 
  return {
    addToBelt: ( p ) => {
      utilities.push( p )
      return ref
    },
    utilities
  }
}
const decorate = ( obj, factoryArray ) => {
 const instances = factoryArray.map( f => f( obj ) )
 return Object.assign( obj, …instances )
}
let batman = comicBookCharacter( ‘Bruce’, ‘Wayne’ )
console.log( batman.realName )
decorate( batman, [ superPower, utilityBelt ] )
batman
 .addPower( ‘money’ )
 .addToBelt( ‘something’ )
 .addPower( ‘strength’)
 .addToBelt( ‘batarang’ )
console.log( batman.powers, batman.utilities )