89 lines
2.1 KiB
TypeScript
89 lines
2.1 KiB
TypeScript
import { utcToZonedTime, zonedTimeToUtc } from "date-fns-tz";
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export const TERMS = ["winter", "spring", "fall"] as const;
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export type Term = typeof TERMS[number];
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export const DATE_FORMAT = "MMMM dd yyyy HH:mm";
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// https://www.typescriptlang.org/docs/handbook/2/narrowing.html#using-type-predicates
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export function isTerm(x: string): x is Term {
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return TERMS.some((term) => x === term);
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}
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export function capitalize(str: string) {
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return str.slice(0, 1).toUpperCase() + str.slice(1);
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}
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// Converts a date to local time
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export function getLocalDateFromEST(date: Date): Date {
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return utcToZonedTime(
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// The date parameter is in EST
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zonedTimeToUtc(date, "America/Toronto"),
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Intl.DateTimeFormat().resolvedOptions().timeZone
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);
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}
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export interface TermYear {
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term: Term;
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year: number;
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}
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export interface GetTermYearOptions {
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goBackwards?: boolean;
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skipCurrent?: boolean;
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}
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export function* getTermYear(
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start?: number | TermYear,
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{ goBackwards = false, skipCurrent = false }: GetTermYearOptions = {}
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) {
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const allTerms = [...TERMS];
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if (goBackwards) {
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allTerms.reverse();
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}
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const today = new Date();
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const todayYear = today.getFullYear();
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const todayTerm = TERMS[Math.trunc(today.getMonth() / 4)];
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start ??= { term: todayTerm, year: todayYear };
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if (typeof start === "number") {
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start = { term: allTerms[0], year: start };
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}
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let currentYear = start.year;
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while (0 <= currentYear && currentYear <= Number.MAX_SAFE_INTEGER) {
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for (const currentTerm of allTerms) {
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if (
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currentYear === start.year &&
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allTerms.indexOf(currentTerm) < allTerms.indexOf(start.term)
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) {
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continue;
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}
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if (
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skipCurrent &&
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currentYear === start.year &&
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currentTerm === start.term
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) {
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continue;
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}
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yield { term: currentTerm, year: currentYear };
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}
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currentYear = currentYear + (goBackwards ? -1 : 1);
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}
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}
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export function getCurrentTermYear() {
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const result = getTermYear().next();
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if (result.done === true) {
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throw new Error("Cannot get current term. Iterator is done.");
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}
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return result.value;
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}
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