ui-formatter

A lightweight, zero-dependency TypeScript utility library for formatting dates, times, numbers, and phone numbers.

Designed for applications that require high performance, small bundle size, and no external dependencies.

Features

• 🚀 Zero dependencies
• ⚡ High-performance implementations
• 📅 Date formatting
• 🕒 Time formatting
• 🔢 Number formatting
• ☎️ Phone/Fax formatting
• 🧹 Phone normalization
• 💯 TypeScript support
• 🌍 Works in Browser and Node.js

Installation

npm install ui-formatter

or

yarn add ui-formatter

Quick Example

import {
    formatDate,
    formatDateTime,
    formatNumber,
    formatInteger,
    formatPhone
} from "ui-formatter"

const date = new Date()

formatDate(date, "MM/dd/yyyy")
// 07/02/2026

formatDateTime(date, "yyyy-MM-dd")
// 2026-07-02 14:35

formatNumber(1234567.89, 2)
// 1,234,567.89

formatInteger(1000000)
// 1,000,000

formatPhone("8005551234")
// 800 555-1234

API

Date Utilities

getDateFormat()

Returns the default date format.

const format = getDateFormat()

// M/d/yyyy

addDays()

Returns a new date with the specified number of days added.

const tomorrow = addDays(new Date(), 1)

formatDate()

Formats a Date using a custom format.

Supported tokens:

| Token | Description | |--------|-------------| | yyyy | 4-digit year | | yy | 2-digit year | | MM | 2-digit month | | M | Month | | dd | 2-digit day | | d | Day |

Example

formatDate(new Date(), "yyyy-MM-dd")

// 2026-07-02

formatTime()

Returns

HH:mm

Example

formatTime(new Date())

// 15:30

formatLongTime()

Returns

HH:mm:ss

Example

formatLongTime(new Date())

// 15:30:45

formatFullTime()

Returns

HH:mm:ss.SSS

Example

formatFullTime(new Date())

// 15:30:45.123

formatDateTime()

Formats

<Date> <HH:mm>

Example

formatDateTime(new Date(), "yyyy-MM-dd")

// 2026-07-02 15:30

formatLongDateTime()

Formats

<Date> <HH:mm:ss>

formatFullDateTime()

Formats

<Date> <HH:mm:ss.SSS>

datetimeToString()

Converts a Date into ISO-like format.

datetimeToString(new Date())

// 2026-07-02T15:30:45

dateToString()

Returns a compact timestamp.

dateToString(new Date())

// 20260702153045

Milliseconds may be included.

dateToString(new Date(), true)

// 20260702153045123

Number Utilities

formatInteger()

Formats an integer with thousands separators.

formatInteger(123456789)

// 123,456,789

Custom separator

formatInteger(123456789, ".")

// 123.456.789

formatNumber()

Formats decimal numbers.

formatNumber(1234567.89, 2)

// 1,234,567.89

Custom separators

formatNumber(
    1234567.89,
    2,
    ",",
    "."
)

// 1.234.567,89

Phone Utilities

normalizePhone()

Removes all characters except digits and +.

normalizePhone("(800) 555-1234")

// 8005551234

normalizeFax()

Alias of

normalizePhone()

formatPhone()

Formats phone numbers into a readable representation.

formatPhone("8005551234")

// 800 555-1234

Supports

• US numbers
• international numbers
• partial numbers

formatFax()

Formats fax numbers.

formatFax("0212345678")

// 02-12345678

Utility Functions

isNotEmpty()

Checks whether an array or string is not empty.

isNotEmpty([])

// false

isNotEmpty("hello")

// true

isChecked()

Utility for HTML templates.

isChecked(true)

// checked

isChecked(false)

// ""

Can also compare string values.

isChecked("admin", "admin")

// checked

Design Goals

This library is designed with the following principles:

• Zero runtime dependencies
• High performance
• Minimal allocations
• Small bundle size
• Predictable behavior
• Browser and Node compatibility

Several implementations avoid regular expressions and repeated string concatenation in favor of allocation-friendly algorithms.

Performance

The library includes optimized implementations for:

• Manual date parsing
• Number formatting
• Integer formatting
• Phone normalization

Many functions use:

• single-pass parsing
• preallocated buffers
• minimal temporary objects

making them suitable for high-throughput applications.

Browser Support

Works in:

• Chrome
• Firefox
• Safari
• Edge
• Node.js
• Bun
• Deno

TypeScript

Fully written in TypeScript.

No additional typings are required.