mnth

library2.0.0jsnpmunverified

mnth is a lightweight, framework-agnostic utility library designed to simplify the generation of calendar-style month data. Its primary function, `getCalendarMonth`, takes a `Date` object and an optional configuration (e.g., `firstDayOfWeek`) to return a 2D array of `Date` objects, representing all days visible in a given month's calendar view, including leading and trailing days from adjacent months. Currently at version 2.0.0, the package provides a focused solution for UI components like datepickers and full calendars, distinguishing itself by providing raw `Date` objects for maximum flexibility rather than pre-formatted strings or complex component structures. It ships with TypeScript types, promoting strong type checking and improved developer experience. The library is part of the `nextools/metarepo` monorepo.

web-framework serialization

npm install mnth

github ↗package ↗

INSTALL

IMPORT

SIG · MNTH

mnth

web-frameworkjavascriptv2.0.0

Install

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Import

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Pass rate

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Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

getCalendarMonth

✓ import { getCalendarMonth } from 'mnth';

✗ const { getCalendarMonth } = require('mnth');

mnth v2.0.0 is primarily designed for ES Modules. While CommonJS might work with transpilation, direct `require` is not the idiomatic or guaranteed approach. The package ships with TypeScript types for enhanced development.

Options

✓ import type { Options } from 'mnth';

Importing types uses the `import type` syntax for clarity and to ensure they are stripped during compilation, though a regular `import` might also work depending on your TypeScript configuration.

This example demonstrates how to use `getCalendarMonth` to generate a 2D array of `Date` objects for a given month, showing both default and custom `firstDayOfWeek` options. It then formats and logs the day numbers for each week.

import { getCalendarMonth } from 'mnth'; // Get the calendar month for April 2018, with default options (Monday as first day of week) const date = new Date('2018-04-01T12:00:00.000Z'); // Using UTC to avoid local timezone issues on initialization const calendarMonth = getCalendarMonth(date); console.log('Calendar for April 2018 (default options):'); calendarMonth.forEach(week => { console.log(week.map(day => day.toLocaleDateString('en-US', { day: '2-digit' })).join(', ')); }); // Example with custom options: Sunday as the first day of the week const sundayFirstCalendar = getCalendarMonth(date, { firstDayOfWeek: 0 }); console.log('\nCalendar for April 2018 (Sunday as first day):'); sundayFirstCalendar.forEach(week => { console.log(week.map(day => day.toLocaleDateString('en-US', { day: '2-digit' })).join(', ')); }); /* Expected output structure (values depend on exact date/timezone): Calendar for April 2018 (default options): 26, 27, 28, 29, 30, 31, 01 02, 03, 04, 05, 06, 07, 08 09, 10, 11, 12, 13, 14, 15 16, 17, 18, 19, 20, 21, 22 23, 24, 25, 26, 27, 28, 29 30, 01, 02, 03, 04, 05, 06 Calendar for April 2018 (Sunday as first day): 25, 26, 27, 28, 29, 30, 31 01, 02, 03, 04, 05, 06, 07 08, 09, 10, 11, 12, 13, 14 15, 16, 17, 18, 19, 20, 21 22, 23, 24, 25, 26, 27, 28 29, 30, 01, 02, 03, 04, 05 */

Debug

Known issues

gotchaThe `firstDayOfWeek` option expects a number where `0` is Sunday, `1` is Monday, and so on, up to `6` for Saturday. Misinterpreting these values (e.g., assuming `1` is Sunday) can lead to incorrect calendar layouts.

fix

Always refer to the documentation for the `firstDayOfWeek` option: `0` for Sunday, `1` for Monday (default), `6` for Saturday.

affects: >=2.0.0

gotchaJavaScript `Date` objects are mutable. While `mnth` returns new `Date` objects in its 2D array, any subsequent modification to these `Date` instances in your application will affect the object directly. Be mindful of this when passing `Date` objects around or manipulating them after `getCalendarMonth` has returned.

fix

If immutability is crucial, clone `Date` objects from the `mnth` output before performing modifications (e.g., `new Date(day.getTime())`).

affects: >=2.0.0

gotchaHandling timezones with native JavaScript `Date` objects can be a source of common errors. `mnth` operates based on the `Date` object you provide, which will inherently have a timezone context (either UTC or local, depending on how it was created). Ensure your input `Date` objects and subsequent display logic align with your desired timezone handling to avoid unexpected shifts.

fix

For consistent behavior, especially in applications serving users across different timezones, consider creating input `Date` objects in UTC (e.g., `new Date('YYYY-MM-DDTHH:MM:SSZ')`) and handle display-side timezone conversions explicitly, or use dedicated internationalization APIs.

affects: >=2.0.0

Errors

Common errors & fixes

TypeError: Cannot destructure property 'getCalendarMonth' of 'mnth' as it is undefined.

Attempting to use CommonJS `require` syntax on a package primarily designed for ES Modules without proper transpilation or configuration. `mnth` exports `getCalendarMonth` as a named ES Module export.

fix

Ensure your project is configured for ES Modules (e.g., `"type": "module"` in `package.json` for Node.js) and use `import { getCalendarMonth } from 'mnth';`. If you must use CommonJS, you might need a bundler like Webpack or Rollup to transpile ESM to CJS, or explore dynamic `import()`.

RangeError: Invalid Date

The `Date` object passed to `getCalendarMonth` is invalid or represents an unparseable date. This can happen if the `Date` constructor received an invalid string or number.

fix

Validate your input `Date` object before passing it to `getCalendarMonth`. Check if `isNaN(date.getTime())` is true, which indicates an invalid Date. Ensure date strings are in a consistent, parsable format (e.g., ISO 8601).

Upgrade

Version history

2.0.0latest on npm

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Dependencies

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Agent activity

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node

Resources

githubhttps://github.com/nextools/metarepo ↗

packagehttps://www.npmjs.com/package/mnth ↗