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Simplified getRelativeTimeString
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// from https://twitter.com/Steve8708/status/1504131981444980739 | |
// simplified to a function body of 8 tidy lines | |
// no loop needed, no 2d array of 3-tuples needed | |
// just 2 arrays, a findIndex call, and some indexing :) | |
export function getRelativeTimeString( | |
date: Date | number, | |
lang = "en" | |
): string { | |
const timeMs = typeof date === "number" ? date : date.getTime(); | |
const deltaSeconds = Math.round((timeMs - Date.now()) / 1000); | |
const cutoffs = [60, 3600, 86400, 86400 * 7, 86400 * 30, 86400 * 365, Infinity]; | |
const units: Intl.RelativeTimeFormatUnit[] = ["second", "minute", "hour", "day", "week", "month", "year"]; | |
const unitIndex = cutoffs.findIndex(cutoff => cutoff > Math.abs(deltaSeconds)); | |
const divisor = unitIndex ? cutoffs[unitIndex - 1] : 1; | |
const rtf = new Intl.RelativeTimeFormat(lang, { numeric: "auto" }); | |
return rtf.format(Math.floor(deltaSeconds / divisor), units[unitIndex]); | |
} | |
// alternate: init the arrays + RTF only once, keep in closure | |
// worthwhile if doing lots of calls, RTF init isn't free | |
// this is probably how I would actually do this for prod shipped code I guess | |
export function makeRelativeTimeStringGetter(lang = "en") { | |
const cutoffs = [60, 3600, 86400, 86400 * 7, 86400 * 30, 86400 * 365, Infinity]; | |
const units: Intl.RelativeTimeFormatUnit[] = ["second", "minute", "hour", "day", "week", "month", "year"]; | |
const rtf = new Intl.RelativeTimeFormat(lang, { numeric: "auto" }); | |
return function getRelativeTimeString(date: Date | number): string { | |
const timeMs = typeof date === "number" ? date : date.getTime(); | |
const deltaSeconds = Math.round((timeMs - Date.now()) / 1000); | |
const unitIndex = cutoffs.findIndex(cutoff => cutoff > Math.abs(deltaSeconds)); | |
const divisor = unitIndex ? cutoffs[unitIndex - 1] : 1; | |
return rtf.format(Math.floor(deltaSeconds / divisor), units[unitIndex]); | |
} | |
} | |
console.log(getRelativeTimeString(Date.now() - 100)); // now | |
console.log(getRelativeTimeString(Date.now() - 10000)); // 10 seconds ago | |
console.log(getRelativeTimeString(Date.now() - 100000)); // 2 minutes ago | |
console.log(getRelativeTimeString(Date.now() - 10000000)); // 3 hours ago | |
console.log(getRelativeTimeString(Date.now() + 10000)); // in 10 seconds | |
console.log(getRelativeTimeString(Date.now() + 100000)); // in 1 minute | |
console.log(getRelativeTimeString(Date.now() + 10000000)); // in 2 hours | |
console.log(getRelativeTimeString(Date.now() + 100000000)); // tomorrow | |
console.log(getRelativeTimeString(Date.now() + 1000000000)); // next week | |
console.log(getRelativeTimeString(Date.now() + 10000000000)); // in 3 months | |
console.log(getRelativeTimeString(Date.now() + 100000000000)); // in 3 years |
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