SOURCE

Array.prototype.some = function (callbak) {
  let len = this.length
  let result
  for (let i = 0; i < len; i++) {
    result = callbak(this[i], i, this)
    if (result) {
      break
    }
  }
  return !!result
}


var a = [1, 2, 3]

let result = a.some((item, index, context) => {
  console.log(item)
  return item === 2
})

console.log(result)