time-pray

Prayer Times Calculator for JavaScript Based on Praytimes.org.

This is a refactor of the original Praytimes.org source code to make it more usable with npm and JavaScript. The output formats have also been updated - see Output Philosophy section for more details.

Installation

Install with npm:

npm install time-pray

Calculation Methods

Supported methods:

• MWL - Muslim World League
• ISNA - Islamic Society of North America
• Egypt - Egyptian General Authority of Survey
• Makkah - Umm al-Qura, Makkah
• Karachi - University of Islamic Sciences, Karachi
• Tehran - Institute of Geophysics, University of Tehran
• Jafari - Shia Ithna Ashari, Leva Institute, Qum

Usage

Import the functions:

import { getPrayerCalculator, methods } from "time-pray";

Create calculator:

const calculator = getPrayerCalculator(methods.MWL);

Get prayer times:

const times = calculator(
    {
        longitude: -0.1,
        latitude: 51.5,
    },
    today(), // or getDatePartsUTC(new Date("2022-11-12")) or [2022,11,12]
);

Output times:

for (const time of Object.keys(times)) {
    console.log(times[time].toISOString());
}

Configuration

For most users the already implemented calculation methods are enough, for example:

let calculator = getPrayerCalculator(methods.Jafari); // create a calculator based on Jafari method's parameters

Warning: these parameters aren't meant to be used as a way of tuning times for precaution - there is another function for this purpose (see tuning)!

But if you want more advanced usage, you can provide your own calculation parameters. The default method is MWL. Anything else will override it. For details see Praytimes Manual.

Example Configuration

const params: Params = {
    imsak: { minutes: 10 },
    fajr: { degree: 18 },
    dhuhr: { minutes: 0 },
    asr: { factor: 1 },
    maghrib: { minutes: 0 },
    isha: { degree: 17 },
    midnight: "Standard",
    highLats: "NightMiddle",
};

Here is a description of the parameters:

imsak

• Type: Degrees | Minutes
• Default: {minutes: 10}

The sun angle below horizon or minutes before Fajr for Imsak time.

fajr

• Type: Degrees
• Default: {degree: 18}

The sun angle below horizon to use for Fajr time. In degrees.

dhuhr

• Type: Minutes
• Default: {minutes: 0}

The minutes after (or before with negative) midday for Dhuhr.

asr

• Type: {factor: number}
• Default: {factor: 1}

The shadow factor to use for Asr time.

maghrib

• Type: Degrees | Minutes
• Default: {minutes: 0}

The sun angle below horizon or minutes after sunset for Maghrib.

isha

• Type: Degrees | Minutes
• Default: {degree: 17}

The sun angle below horizon or minutes after Maghrib for Isha.

midnight

• Type: MidnightMethod ("Standard" | "Jafari")
• Default: "Standard"

The method for calculating midnight. "Standard" or "Jafari".

highLats

• Type: HighLatsMethod
• Default: "NightMiddle"

The higher latitude adjustment method. "None", "NightMiddle", "OneSeventh", or "AngleBased".

API Reference

getCalculator(settings)

Creates a prayer time calculator initialized with given settings.

Returns a function that can be called to get prayer times by passing location and date.

calculator(location, date)

Given a location and date, computes prayer times.

• location - Object with latitude and longitude
• date - JavaScript Date object

Returns an object with prayer times mapped to time names. Prayer times are Date objects.

Time names:

• imsak
• fajr
• sunrise
• dhuhr
• asr
• sunset
• maghrib
• isha
• midnight

tuning

You can tune times for precaution using the tune method:

import { tune } from "time-pray";

// Calculate times
const tunedTimes = tune({ fajr: -3 }, times);

The first parameter is a map of pray times to a number of minutes to adjust the time.

For example:

{
  fajr: 2023-08-10T08:17:23.544Z,
  // ...
}

Becomes:

{
  fajr: 2023-08-10T08:14:23.544Z,
  // ...
}

Formatting

Format

Formats prayer times into a desired format.

format(times, format, timezone?)

Parameters:

• times (PraytimesOutput) - Times object to format
• format (Format) - Format preset. Options:
  • "24h" - 24 hour
  • "12h" - 12 hour with AM/PM
  • "12hNS" - 12 hour with no suffix
  • "Float" - Floating point hours
• timezone (number) - Optional UTC offset in hours

Returns: Object with formatted times.

Example:

const formatted = format(
    {
        fajr: new Date("2023-03-01T13:15:00Z"),
        dhuhr: new Date("2023-03-01T20:30:00Z"),
        asr: new Date("2023-03-02T00:45:00Z"),
    },
    "12h",
    -8,
);

// {
//   fajr: "5:15AM",
//   dhuhr: "12:30PM",
//   asr: "4:45PM"
// }

formatTime

Formats a Date object into a time string.

formatTime(format, date, timezone?)

Parameters:

• format (Format) - Format preset
• date (Date) - Date to format
• timezone (number) - Optional UTC offset in hours

Returns: (string) - Formatted time string

Example:

formatTime("24h", new Date());

Date functions

getDatePartsUTC

Returns an array of [year, month, day] representing the UTC date.

getDatePartsUTC(date);

Parameters:

• date (Date) - Input date

Returns: (Number[]) - Array of [year, month, day]

Example:

getDatePartsUTC(new Date());

today

Returns the current date as an array of [year, month, day] in the local timezone.

today();

Returns: (Number[]) - Array of [year, month, day]

getDatePartsLocal

Returns an array of [year, month, day] representing the date in the local timezone.

getDatePartsLocal(date);

Parameters:

• date (Date) - Input date

Returns: (Number[]) - Array of [year, month, day]

Example:

getDatePartsLocal(new Date());

Output Philosophy

The original code output prayer times as strings (e.g. '12:20').

This package outputs Date objects, which better represent prayer times as absolute moments in time, independent of timezone.

The format utility can be used to convert to strings as needed:

import { format } from "time-pray";

const formattedTimes = format(times);

Tests

Tests enforce accuracy within 50ms of original Praytimes.org calculations using a dataset of 150,000 cities globally. Dates, calculation methods, and parameters are randomly generated for robust testing.

The codebase is 100% covered by unit tests.

To run tests and view coverage:

npm run test:cov

This will execute the test suite and generate a coverage report.

Results:

 PASS  src/tune.test.ts
 PASS  src/format.test.ts
 PASS  tests/match.test.ts (85.119 s)
----------------|---------|----------|---------|---------|-------------------
File            | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
----------------|---------|----------|---------|---------|-------------------
All files       |     100 |      100 |    93.1 |     100 |
 calculator.ts  |     100 |      100 |     100 |     100 |
 format.ts      |     100 |      100 |     100 |     100 |
 index.ts       |     100 |      100 |       0 |     100 |
 method-data.ts |     100 |      100 |     100 |     100 |
 methods.ts     |     100 |      100 |     100 |     100 |
 tune.ts        |     100 |      100 |     100 |     100 |
----------------|---------|----------|---------|---------|-------------------

Test Suites: 3 passed, 3 total
Tests:       17 passed, 17 total
Snapshots:   0 total
Time:        85.388 s
Ran all test suites.
Done in 85.65s.

Credits

PrayTimes.js is based on PrayTimes. Cities dataset from countries-states-cities-database.

License

GNU GPL v3.0 - see LICENSE