breezewiki/static/countdown.js

53 lines
1.6 KiB
JavaScript

// countdown timer for gacha enthusiasts
// sample: bandori/wiki/BanG_Dream!_Wikia
// sample: ensemble-stars/wiki/The_English_Ensemble_Stars_Wiki
import {h, htm, render, signal, computed, effect} from "./preact.js"
const html = htm.bind(h)
const now = signal(Date.now())
setInterval(() => now.value = Date.now(), 1000)
const units = [
["w", 7*24*60*60*1000],
["d", 24*60*60*1000],
["h", 60*60*1000],
["m", 60*1000],
["s", 1000]
]
function getDisplayTime(datetime, now, or) {
let difference = datetime - now
let foundSignificantField = false
if (difference > 0) {
return units.map(([letter, duration], index) => {
const multiplier = Math.floor(difference / duration)
difference -= multiplier * duration
if (multiplier > 0 || foundSignificantField) {
foundSignificantField = true
return multiplier + letter
}
}).filter(s => s).join(" ")
} else if (or) {
return or
} else {
return `[timer ended on ${new Date(datetime).toLocaleString()}]`
}
}
function Countdown(props) {
return html`<span>${props.display}</span>`
}
document.querySelectorAll(".countdown").forEach(eCountdown => {
// grab information and make variables
const eDate = eCountdown.querySelector(".countdowndate")
const eOr = eCountdown.nextElementSibling
const or = eOr?.textContent
const datetime = new Date(eDate.textContent).getTime()
// the mapped signal
const display = computed(() => getDisplayTime(datetime, now.value, or))
// clear content and render
while (eDate.childNodes[0] !== undefined) eDate.childNodes[0].remove()
render(html`<${Countdown} display=${display} />`, eDate);
})