DateFromTime.js

'use strict';

var GetIntrinsic = require('get-intrinsic');

var $EvalError = GetIntrinsic('%EvalError%');

var DayWithinYear = require('./DayWithinYear');
var InLeapYear = require('./InLeapYear');
var MonthFromTime = require('./MonthFromTime');

// https://262.ecma-international.org/5.1/#sec-15.9.1.5

module.exports = function DateFromTime(t) {
	var m = MonthFromTime(t);
	var d = DayWithinYear(t);
	if (m === 0) {
		return d + 1;
	}
	if (m === 1) {
		return d - 30;
	}
	var leap = InLeapYear(t);
	if (m === 2) {
		return d - 58 - leap;
	}
	if (m === 3) {
		return d - 89 - leap;
	}
	if (m === 4) {
		return d - 119 - leap;
	}
	if (m === 5) {
		return d - 150 - leap;
	}
	if (m === 6) {
		return d - 180 - leap;
	}
	if (m === 7) {
		return d - 211 - leap;
	}
	if (m === 8) {
		return d - 242 - leap;
	}
	if (m === 9) {
		return d - 272 - leap;
	}
	if (m === 10) {
		return d - 303 - leap;
	}
	if (m === 11) {
		return d - 333 - leap;
	}
	throw new $EvalError('Assertion failed: MonthFromTime returned an impossible value: ' + m);
};