go-propername

A Go library for sanitizing and proper casing of human names written in Latin script. Zero dependencies, MIT licensed.

A port of the propername npm package.

Installation

go get github.com/vgavara/go-propername

Usage

import "github.com/vgavara/go-propername"

propername.ToNameCase("john smith")                               // → "John Smith"
propername.ToNameCase("JOHN SMITH")                               // → "John Smith"
propername.ToNameCase("ludwig van beethoven")                     // → "Ludwig van Beethoven"
propername.ToNameCase("mcdonald")                                 // → "McDonald"
propername.ToNameCase("macgregor")                                // → "MacGregor"
propername.ToNameCase("o'brien")                                  // → "O'Brien"
propername.ToNameCase("marie-anne van der berg")                  // → "Marie-Anne van der Berg"

// Trim first to sanitize whitespace, then case
propername.ToNameCase(propername.Trim("  john  smith  "))         // → "John Smith"

// Trim only
propername.Trim("  john  smith  ")                                // → "john smith"

API

ToNameCase(name string) string

Converts a human name string to proper name casing. Whitespace structure is preserved as-is — call Trim first if you want whitespace sanitized.

• Splits on whitespace, hyphens (-), and apostrophe variants (', ' U+2019, ʼ U+02BC)
• Capitalizes each word, except particles which stay lowercase unless they appear at the start of the string
• Applies Mc/Mac prefix capitalization rules

Trim(name string) string

Removes leading and trailing whitespace and collapses internal runs of whitespace to a single space.

Supported conventions

Word boundaries

The following characters are treated as word boundaries (the segment after each is capitalized):

• Whitespace
• Hyphens: goodfellow-smith → Goodfellow-Smith
• Apostrophes (', ', ʼ): o'connor → O'Connor

Prefixes

Prefix	Example input	Output
Mc	mcdonald	McDonald
Mac	macgregor	MacGregor

Lowercase particles

Particles are kept lowercase unless they appear as the first word of the string.

Culture	Particles
Dutch	van, de, den, der, ten, ter
German	von, zu
French / Italian / Spanish / Portuguese	de, di, da, del, della, degli, dei, las, los, le, la, l', d', dos, das, e
Welsh	ap, ab, ferch, verch
Arabic (romanized)	al, el, bin, bint, ibn, abu
Scottish	of

Out of scope (v0)

• Non-Latin scripts (Arabic, Chinese, Japanese, Korean, Cyrillic, etc.)
• Full name parsing (splitting into first / last / middle)
• Prefix/suffix handling (Mr., Dr., PhD, etc.)

License

MIT