charts/src/js/utils/date-utils.js
2018-03-29 02:21:48 +05:30

74 lines
1.9 KiB
JavaScript

// Playing around with dates
export const NO_OF_YEAR_MONTHS = 12;
export const NO_OF_DAYS_IN_WEEK = 7;
export const DAYS_IN_YEAR = 375;
export const NO_OF_MILLIS = 1000;
export const SEC_IN_DAY = 86400;
export const MONTH_NAMES = ["January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"];
export const MONTH_NAMES_SHORT = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
// https://stackoverflow.com/a/11252167/6495043
function treatAsUtc(date) {
let result = new Date(date);
result.setMinutes(result.getMinutes() - result.getTimezoneOffset());
return result;
}
export function getDdMmYyyy(date) {
let dd = date.getDate();
let mm = date.getMonth() + 1; // getMonth() is zero-based
return [
(dd>9 ? '' : '0') + dd,
(mm>9 ? '' : '0') + mm,
date.getFullYear()
].join('-');
}
export function clone(date) {
return new Date(date.getTime());
}
export function timestampSec(date) {
return date.getTime()/NO_OF_MILLIS;
}
export function timestampToMidnight(timestamp, roundAhead = false) {
let midnightTs = Math.floor(timestamp - (timestamp % SEC_IN_DAY));
if(roundAhead) {
return midnightTs + SEC_IN_DAY;
}
return midnightTs;
}
export function getWeeksBetween(startDate, endDate) {
return Math.ceil(getDaysBetween(startDate, endDate) / NO_OF_DAYS_IN_WEEK);
}
export function getDaysBetween(startDate, endDate) {
let millisecondsPerDay = SEC_IN_DAY * NO_OF_MILLIS;
return (treatAsUtc(endDate) - treatAsUtc(startDate)) / millisecondsPerDay;
}
export function getMonthName(i, short=false) {
let monthName = MONTH_NAMES[i];
return short ? monthName.slice(0, 3) : monthName;
}
// mutates
export function setDayToSunday(date) {
const day = date.getDay();
if(day !== NO_OF_DAYS_IN_WEEK) {
addDays(date, (-1) * day);
}
return date;
}
// mutates
export function addDays(date, numberOfDays) {
date.setDate(date.getDate() + numberOfDays);
}