Using arrow functions

arrow_functions.js

const dragonEvents = [
  {type: 'attack', value: 40, victim: 'dorkman'},
  {type: 'sleep', value: 10},
  {type: 'attack', value: 20, victim: 'aquaman'},
  {type: 'attack', value: 40, victim: 'dorkman'},
]

const v = 'dorkman';
const field = 'victim';
const selectVictim = (e) => e[field] === v;
const selectAttack = e => e.type === 'attack';
const initialValue = 9
const summer = (total, v) => ( total + v) ; 
const summerInitialValue = (initialValue) => (summer, initialValue) 
const myReduce = (reducer, initialValue) => (summer, initialValue)

const totalDamageOnDorkman = dragonEvents
                      .filter(selectAttack)
                      .filter(selectVictim)
                      .map(e => e.value)
                      .reduce(summer,4) //works
// Does not work      .reduce(summerInitialValue)
// Does not work      [myReduce]


console.log(totalDamageOnDorkman)