jgrahamc/gist:9811cdc25db6ea6226255e9f4913ff45

## gistfile1.txt
addEventListener('fetch', event => {
  event.respondWith(getLogarithm(event.request))
})

async function getLogarithm(request) {
  const url = new URL(request.url)

  if (!url.searchParams.has("int")) {
    return new Response("Missing query parameter 'int'", {status: 403})
  }

  const stringInt = url.searchParams.get("int")
  const paddedInt = padTo(4, stringInt)
  const intInt = parseInt(stringInt)

  if ((intInt < 1) || (intInt > 9999)) {
    return new Response("'int' must be between 1 and 9999", {status: 403})
  }

  const retrieved = await CARD.get(paddedInt)

  if (retrieved === null) {
    const logarithm = Math.log10(intInt)
    const value = Math.round((logarithm - Math.floor(logarithm))*10000000)
    const paddedValue = padTo(7, value)
    CARD.put(paddedInt, paddedValue)

    return makeCard(paddedInt, paddedValue, false)
  }

  const parsed = JSON.parse(retrieved)
  return makeCard(paddedInt, parsed.value, true)
}

async function makeCard(l, r, found) {
  var html = '<html><body style="font-family: monospace;"><table style="width: 320px; border: 2px solid black"><thead><tr><td></td><td colspan="4" align="center">Number.</td><td></td><td></td><td></td><td colspan="7" align="center">Table.</td><td></td></tr></thead><tbody>'
  html += '<tr style="outline: solid 1px;"><td></td>'
  html += perDigit(l)
  html += "<td></td><td></td><td></td>"
  html += perDigit(r)
  html += "<td></td></tr>"
  for (var j = 0; j < 9; j++) {
    html += "<tr><td></td>"
    html += circles(j, l)
    html += "<td></td><td></td><td></td>"
    html += circles(j, r)
    html += "<td></td></tr>"
  }

  html += "</tbody></table>"
  html += "<br>Card was "
  html += found?"retrieved":"added"
  html += "</body></html>"

  return new Response(html, {headers: {"Content-Type": "text/html"}})
}

function perDigit(s) {
  var html = ''
  for (var i = 0; i < s.length; i++) {
      html += "<td>"
      html += s.substr(i, 1)
      html += "</td>"
  }
  return html
}

function circles(j, s) {
  var html = ''
  for (var i = 0; i < s.length; i++) {
    html += "<td>"
    html += parseInt(s.substr(i, 1)) > j?'&#9679;':'&#9675;'
    html += "</td>"
  }
  return html
}

function padTo(n, s) {
  return ("0".repeat(n-1) + s).substr(-n)
}
	addEventListener('fetch', event => {
	event.respondWith(getLogarithm(event.request))
	})

	async function getLogarithm(request) {
	const url = new URL(request.url)

	if (!url.searchParams.has("int")) {
	return new Response("Missing query parameter 'int'", {status: 403})
	}

	const stringInt = url.searchParams.get("int")
	const paddedInt = padTo(4, stringInt)
	const intInt = parseInt(stringInt)

	if ((intInt < 1) \|\| (intInt > 9999)) {
	return new Response("'int' must be between 1 and 9999", {status: 403})
	}

	const retrieved = await CARD.get(paddedInt)

	if (retrieved === null) {
	const logarithm = Math.log10(intInt)
	const value = Math.round((logarithm - Math.floor(logarithm))*10000000)
	const paddedValue = padTo(7, value)
	CARD.put(paddedInt, paddedValue)

	return makeCard(paddedInt, paddedValue, false)
	}

	const parsed = JSON.parse(retrieved)
	return makeCard(paddedInt, parsed.value, true)
	}

	async function makeCard(l, r, found) {
	var html = '<html><body style="font-family: monospace;"><table style="width: 320px; border: 2px solid black"><thead><tr><td></td><td colspan="4" align="center">Number.</td><td></td><td></td><td></td><td colspan="7" align="center">Table.</td><td></td></tr></thead><tbody>'
	html += '<tr style="outline: solid 1px;"><td></td>'
	html += perDigit(l)
	html += "<td></td><td></td><td></td>"
	html += perDigit(r)
	html += "<td></td></tr>"
	for (var j = 0; j < 9; j++) {
	html += "<tr><td></td>"
	html += circles(j, l)
	html += "<td></td><td></td><td></td>"
	html += circles(j, r)
	html += "<td></td></tr>"
	}

	html += "</tbody></table>"
	html += "<br>Card was "
	html += found?"retrieved":"added"
	html += "</body></html>"

	return new Response(html, {headers: {"Content-Type": "text/html"}})
	}

	function perDigit(s) {
	var html = ''
	for (var i = 0; i < s.length; i++) {
	html += "<td>"
	html += s.substr(i, 1)
	html += "</td>"
	}
	return html
	}

	function circles(j, s) {
	var html = ''
	for (var i = 0; i < s.length; i++) {
	html += "<td>"
	html += parseInt(s.substr(i, 1)) > j?'●':'○'
	html += "</td>"
	}
	return html
	}

	function padTo(n, s) {
	return ("0".repeat(n-1) + s).substr(-n)
	}