JSON.stringify polyfill

// This implementation does not work with Symbols, BigInts

function stringify(data) {
  if (data === undefined)
    return undefined
  if (data === null)
    return 'null'
  if (data.toString() === "NaN")
    return 'null'
  if (data === Infinity)
    return 'null'
  if (data.constructor === String)
    return '"' + data.replace(/"/g, '\\"') + '"'
  if (data.constructor === Number)
    return String(data)
  if (data.constructor === Boolean)
    return data ? 'true' : 'false'
  if (data.constructor === Array)
    return '[' + data.reduce((acc, v) => {
      if (v === undefined || v === NaN || v === Infinity)
        return [...acc, 'null']
      else
        return [...acc, stringify(v)]
    }, []).join(',') + ']'
  if (data.constructor === Object)
    return '{' + Object.keys(data).reduce((acc, k) => {
      if (data[k] === undefined)
        return acc
      else
        return [...acc, stringify(k) + ':' + stringify(data[k])]
    }, []).join(',') + '}'

    return '{}'
}