node script that runs a timer while the lid is open, pauses on lid close. Macos only.

timer.js

const exec = require("node:util").promisify(require("node:child_process").exec)

const get = (l, n) => (l == null ? null : l.length <= n ? null : l[n])

const lid_open = async () => {
  const { stdout: res } = await exec(
    "ioreg -r -k AppleClamshellState -d 4 | grep AppleClamshellState | head -1"
  )
  const re = /.*"AppleClamshellState" = (No|Yes).*/
  return get(re.exec(res), 1) == "No"
}

var timer = 1000 * 60 * 25
var open = true

const main = async () => {
  var start = Date.now()
  console.log("Started:", new Date(start).toLocaleTimeString())
  const f = async () => {
    const was_open = open
    open = await lid_open()

    if (was_open && !open) {
      console.log("Paused:", new Date(start).toLocaleTimeString())
    }

    if (!was_open && open) {
      console.log("Resumed:", new Date(start).toLocaleTimeString())
    }

    console.log(
      open,
      `${("0" + Math.floor(timer / 60000)).slice(-2)}:${(
        "0" + Math.floor((timer % 60000) / 1000)
      ).slice(-2)}`
    )

    const cur = Date.now()

    if (!was_open && open) {
      start = cur
    } else {
      const delta = cur - start
      start = cur
      if (open) timer -= delta
    }

    if (timer <= 0) {
      exec("say done")
    }

    setTimeout(f, 1000)
  }

  f()
}

main()