@technobuddha/library/getDayOfYear/getDayOfYear.ts

A large library of useful functions

import { ticksPerDay }      from '../constants';
import floor                from '../floor';
import getBeginningOfYear   from '../getBeginningOfYear';

type Options = {
    UTC?: boolean;
};

export function getDayOfYear(input: Date, { UTC = false }: Options = {}): number {
    return floor((input.getTime() - getBeginningOfYear(input, { UTC }).getTime()) / ticksPerDay, { tolerance: 0.05 }) + 1;
}

export default getDayOfYear;