find_performance.coffee

uuid = -> ~~(Math.random() * 100000)

n = 1000000
list =
  for i in [1..n]
    id: uuid

find = (list, fn) ->
  for i in list
    ret = fn(i)
    if ret then return i
  null

find_by_id = (list, id) ->
  for i in list
    if i.id is id then return i
  null

find_with_indexes = (list, indexes, id) ->
  index = indexes[id]
  return list[index]

create_indexes = (list, key) ->
  indexes = {}
  for i, n in list
    indexes[i[key]] = n

try_count = 10
console.time 'find'
for i in [1..try_count]
  find list, (i)-> i.id is uuid()
console.timeEnd 'find'

console.time 'find_by_id'
for i in [1..try_count]
  find_by_id list, uuid()
console.timeEnd 'find_by_id'

id_indexes = create_indexes list, 'id'
console.time 'find_with_indexes'
for i in [1..try_count]
  find_with_indexes list, id_indexes, uuid()
console.timeEnd 'find_with_indexes'

gistfile1.txt

$ coffee find_performance.coffee 
find: 158ms
find_by_id: 81ms
find_with_indexes: 0ms