Implementation of underscoreJS every and some functions

underline-underscore-every-some.js

const someEven = [1,2,3,4,5]
const allEven = [2,4,6,8,10]

const isEven = (n) => {
  if (n % 2 ===0) return true
  return false
}

const every = (collection, predicate, context) => {
  if (Array.isArray(collection)) {
    for (let i=0; i<collection.length; i++) {
      if (!predicate.call(context, collection[i], i, collection)) {
        //console.log('the element ', collection[i], ' is odd: ', !predicate.call(context, collection[i]))
        console.log('the element ', collection[i], ' is even: ', !predicate.call(context, collection[i]))
        return false
      }
    }
  } else {
    for (let key in collection) {
      if (collection.hasOwnProperty(key)){
        if (!predicate.call(context, collection[key], key, collection)) return false
      }
    }
  }
  return true
}

const some = (collection, predicate, context) => {
  //[!predicate]: short circuit when it is even, not odd. [!every]:Every short circuits with false, so turn that value to true. 
  return !every(collection, (el, key) =>{
    return !predicate.call(context, el, key, collection)
  })
}

//console.log(every(someEven, isEven))
console.log(some(someEven, isEven))