chrome headless pdf generation

gistfile1.txt

const fs = require('fs')
const CDP = require('chrome-remote-interface')

async function waitForNode(client, selector, waitTimeout) {
  const { Runtime } = client
  const getNode = selector => document.querySelector(selector)

  const result = await Runtime.evaluate({
    expression: `(${getNode})(\`${selector}\`)`,
  })

  if (result.result.value === null) {
    const start = new Date().getTime()
    return new Promise((resolve, reject) => {
      const interval = setInterval(async () => {
        if (new Date().getTime() - start > waitTimeout) {
          clearInterval(interval)
          reject(new Error(`wait("${selector}") timed out after ${waitTimeout}ms`))
        }

        const result = await Runtime.evaluate({
          expression: `(${getNode})(\`${selector}\`)`,
        })

        if (result.result.value !== null) {
          clearInterval(interval)
          resolve()
        }
      }, 500)
    })
  }
}

async function run(url, file) {
  const client = await CDP()
  const { Network, Page } = client

  await Promise.all([
    Network.enable(),
    Page.enable(),
  ])

  await Page.navigate({ url })
  await Page.loadEventFired()
  await waitForNode(client, '.pdf', 1000)

  const { data } = await Page.printToPDF({
    paperWidth: 8.27,
    paperHeight: 11.69,
    marginTop: 0,
    marginBottom: 0,
    marginLeft: 0,
    marginRight: 0,
  })

  fs.writeFileSync(file, Buffer.from(data, 'base64'))

  await client.close()
}

run(process.argv[2], process.argv[3]).then(
  () => { process.exit(0) },
  (e) => {
    console.error(e)
    process.exit(-1)
  },
)