javascript - immutable.js 性能与嵌套 map /对象的比较/相等？

Question

我一直在尝试查找有关 immutable.js 在与深层/嵌套对象进行比较时如何执行的信息，特别是在 big-o 表示法方面。有人碰巧知道它是什么吗？

objA = Immutable.Map({
  a: 'test',
  b: Immutable.Map({ ... })
});

objB = Immutable.Map({
  a: 'test',
  b: Immutable.Map({ ... })
});

objA.equals(objB); // not clear what the perf is on this

Answer 1

看看这是否有帮助:

const Immutable = require('immutable')

function test (limit, mutate) {
  const rawA = {}
  var i
  for (i = 0; i < limit; i++) {
    rawA[String(i)] = i
  }
  const rawB = {}
  for (i = 0; i < limit; i++) {
    rawB[String(i)] = i
  }
  if (mutate) {
    rawB['poison'] = false
  }
  if (Object.keys(rawA).length && Object.keys(rawB).length) {
    if (false) {
      console.log('dummy')
    }
  }
  const a = Immutable.Map(rawA)
  const b = Immutable.Map(rawB)
  const timer = process.hrtime()
  if (a.equals(b)) {
    if (false) {
      console.log('dummy')
    }
  }
  return process.hrtime(timer)
}

const sizes = [1, 10, 100, 1000, 10 * 1000, 100 * 1000, 200 * 1000, 400 * 1000, 500 * 1000]
sizes.forEach((limit) => {
  var t1 = 0
  var t2 = 0
  const tries = [1, 2, 3, 4, 5]
  tries.forEach((i) => {
    t1 += test(limit, true)[1]
    t2 += test(limit, false)[1]
  })
console.log(limit,
          t1,
          Math.round(t1 / (tries.length * limit)),
          t2,
          Math.round(t2 / (tries.length * limit)))
})

粗略地说，当映射不相等时，.equals 的性能为 O(1)，当它们相等时，不比 O(n) 差。

1 313329 62666 579815 115963
10 9617 192 293337 5867
100 10873 22 1900225 3800
1000 17505 4 4998441 1000
10000 32060 1 12044412 241
100000 81504 0 211355401 423
200000 99704 0 543211687 543
400000 133836 0 2231794320 1116
500000 77741 0 2877654681 1151