README.md

配列のメモリ使用量確認

$ node memory_new_array.js 
[
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1,
  ... 9900 more items
]
Heap: 2840104 bytes

$ node memory_new_array2.js
[
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
  1, 1, 1, 1,
  ... 9900 more items
]
Heap: 2922088 bytes

memory_new_array.js

const TotalLanes = 10000;

const createLaneMap = (initial) => {
  return new Array(TotalLanes).fill(initial)
}

const arr = createLaneMap(1)
console.log(arr)

const heapUsed = process.memoryUsage().heapUsed
console.log('Heap:', heapUsed, 'bytes')

memory_new_array2.js

const TotalLanes = 10000;

const createLaneMap = (initial) => {
  const arr = []
  for (let i = 0; i < TotalLanes; i++) {
    arr.push(initial)
  }
  return arr
}

const arr = createLaneMap(1)
console.log(arr)

const heapUsed = process.memoryUsage().heapUsed
console.log('Heap:', heapUsed, 'bytes')