benchmark.js

'use strict'

console.log('| items | Embedded literal | Runtime JSON.parse |')
console.log('| -----:| ----------------:| ------------------:|')
for (let n = 1; n <= 65536; n <<= 1) {
  test(n)
}

function test (items) {
  const data = generateTestData(items)

  const codev1 = '(function (x) { return ' + JSON.stringify(data) + ' })'
  const fn1 = eval(codev1)

  const codev2 = '(function (x) { return JSON.parse(' + JSON.stringify(JSON.stringify(data)) + ') })'
  const fn2 = eval(codev2)

  const output = [ items, measure(fn1), measure(fn2) ]
  console.log('| ' + output.join(' | ') + ' |')
}

function generateTestData (items) {
  const obj = {}
  for (let i = 0; i < items; i += 1) {
    const key = 's' + i
    obj[key] = { start: { line: i, column: 0 }, end: { line: i + 1, column: 20 } }
  }
  return obj
}

function measure (fn) {
  let sum = 0
  for (let i = 0; i < 10; i ++) {
    const start = Date.now()
    fn()
    const finish = Date.now()
    sum += finish - start
  }
  return sum / 10
}