Puppeteer: page.content 不是函数

似乎虽然 $# Page的content方法已定义并记录在案，但它并未导出。

const puppeteer = require("puppeteer")

const resolution = {
  x : 1920,
  y : 1080,
}

const args = [
  "--no-first-run",
  "--disable-sync",
  "--disable-gpu",
  "--disable-translate",
  "--disable-background-networking",
  "--single-process",
  `--window-size=${ resolution.x },${ resolution.y }`,
  '--no-sandbox',
  '--disable-setuid-sandbox',
  '--shm-size=1G'
]

const fn = async () => {
  try {
    const browser = await puppeteer.launch({
      headless     : true,
      handleSIGINT : false,
      args         : args,
    })
    const page = await browser.newPage()
    page.on("console", (...args) => {
      for (let i = 0; i < args.length; ++i) { console.log(`${ i }: ${ args[ i ] }`) }
    })

    await page.setViewport({width: resolution.x, height: resolution.y})
    await page.goto('https://ilearnsmarter.com/', {
      waitUntil          : "networkidle"
    })

    console.log(await page.content())

    await page.close()

    browser.close()

  } catch (err) {
    console.log(err)
  }
}

fn()