Tools by Hyunbin

Fully typed JavaScript utilities with ESM and CJS support. Module List

Usage

Node.js

npm i @hyunbinseo/tools
pnpm i @hyunbinseo/tools

// Reference the following section for the full module list.
import { dateToSafeISOString, generatePINString } from '@hyunbinseo/tools';

Browser

<script type="module">
  // Reference the following section for the full module list.
  // The major version number MUST be specified in the pathname.
  import {} from 'https://cdn.jsdelivr.net/npm/@hyunbinseo/[email protected]/dist/index.js';
</script>

Modules

Date to ISO String with Timezone

Returns a YYYY-MM-DDThh:mm:ss+hh:mm ISO 8601 string. (date and time with the offset)

const date = new Date('2024-05-26T00:00:00.000Z');

// 2024-05-26T08:45:00+08:45
dateToISOStringWithOffset(date, '+08:45');
dateToISOStringWithOffset(date, -525);

Date to Day of the Week with Timezone

Returns a number where 0 represents Sunday.

const date = new Date('2024-05-26T11:00:00Z');
dateToDayWithOffset(date, '-12:00'); // 6 — 5/25, Saturday
dateToDayWithOffset(date, '+00:00'); // 0 — 5/26, Sunday
dateToDayWithOffset(date, '+14:00'); // 1 — 5/27, Monday

Date to Safe ISO String

Returns a timestamp string that can be safely used in filename, directory name, etc.

dateToSafeISOString(); // Uses the current time (e.g. 20240402T020408.248Z)
dateToSafeISOString(new Date('2024-05-26T00:00:00+09:00')); // 20240525T150000.000Z

// The outputted string CANNOT be used in JavaScript.
new Date('20240525T150000.000Z'); // Invalid Date

FormData / URLSearchParams to Object

• Converts kebab-case field names to camelCase.
• Outputs a typed object with camelCase keys.

const formData = new FormData(); // new URLSearchParams()
formData.append('event-name', 'Touch Grass');
formData.append('day-index', '0');
formData.append('day-index', '6');

formDataToObject(formData, {
  // kebab-case field names are converted to camelCase.
  get: [
    'event-name', // becomes `eventName` in the object.
  ],
  getAll: [
    // field name and its plural version.
    // becomes `dayIndexes` in the object.
    ['day-index', 'day-indexes'],
  ],
});

{ "eventName": "Touch Grass", "dayIndexes": ["0", "6"] }

type ReturnType = //
  Record<'eventName', FormDataEntryValue | null> &
    Record<'dayIndexes', FormDataEntryValue[] | null>;

The output type can be narrowed using Valibot or other schema libraries.

// { eventName: string; dayIndexes: number[] };
const formObject = parse(fSchema, fObject);

import { formDataToObject } from '@hyunbinseo/tools';
import type { GenericSchema } from 'valibot';
import { array, integer, object, parse, pipe, string, transform } from 'valibot';

const formData = new FormData();
formData.append('day-index', '0');
formData.append('day-index', '6');

// { dayIndexes: FormDataEntryValue[] | null }
const fObject = formDataToObject(formData, {
  getAll: [['day-index', 'day-indexes']],
});

const fSchema = object({
  dayIndexes: array(pipe(string(), transform(Number), integer())),
}) satisfies GenericSchema<typeof fObject, unknown>;
// Ensures that the `dayIndexes` key exists in the object schema.

// { dayIndexes: number[] };
const formObject = parse(fSchema, fObject);

Generate PIN String

Returns a truly random number string using the Crypto.getRandomValues() method.

generatePINString(); // e.g. 270136
generatePINString(8); // e.g. 39534786

To Readonly Array / Map / Set

ReadonlyArray, ReadonlyMap and ReadonlySet types restrict write methods.

// ReadonlyMap<number, number>
const readonlyMap = toReadonly(new Map([[3, 26]]));
readonlyMap.set(3, 27); // Property 'set' does not exist

// ReadonlySet<number | boolean>
const readonlySet = toReadonly(new Set([5, 26, true]));
readonlySet.add(false); // Property 'add' does not exist

// readonly number[]
const readonlyArray = toReadonly([3, 5, 26]);
readonlyArray.push(27); // Property 'push' does not exist

// Readonly<{ year: number }>
const readonlyRecord = toReadonly({ year: 2017 });
// Cannot assign to 'year' because it is a read-only property.
readonlyRecord['year'] = 2024;

Deep-NonNullable Record

const review: { rating?: number } = {};

if (!review.rating) throw new Error();
review; // { rating?: number }
review.rating; // number

if (!hasNonNullableValues(review, ['rating'])) throw new Error();
review; // { rating: number }