Americanize

Americanize rewrites text into American, British, Australian or Canadian spelling, from source written in either American or British English. It ships as the @stunt-double/spelling package. Stunt Double's public sites are written in American English and rewritten in the browser for visitors who read British, Australian or Canadian spelling.

import { localiseSpelling } from "@stunt-double/spelling";

localiseSpelling("Organize the color of the center.", "british");
// 'Organise the colour of the centre.'

localiseSpelling("Analyse the cancelled catalogue.", "american");
// 'Analyze the canceled catalog.'

Australian EnglishCopy Anchor Link

Australian English spells like British English (colour, organise, centre, travelled), so use the 'british' system. There is no separate 'australian' value.

localiseSpelling("Organize a program to analyze the color of the center.", "british");
// 'Organise a program to analyse the colour of the centre.'

"Program" is left as written: it is correct in both systems, and it is the usual Australian spelling for software too. The same goes for New Zealand, Irish and most other Commonwealth English.

InstallCopy Anchor Link

Add @stunt-double:registry=https://npm.pkg.github.com and a GitHub token with read:packages to your .npmrc.

npm install @stunt-double/spelling

No dependencies. Runs anywhere JavaScript does: browsers, Node 20 or later and workers.

How it worksCopy Anchor Link

Every rewrite is a whole word, looked up exactly in a dictionary generated from stems and the suffixes they take. Nothing is rewritten by pattern alone: "promise", "enterprise" and "otherwise" keep their "-ise" in American English, and "four" and "tour" keep their "-our". A word that isn't in the dictionary stays as written.

• Both directions. A British word left in American copy still comes out American.
• Ambiguous words are left alone. Words correct in both systems with different meanings ("practice", "license", "check", "program") are never rewritten towards British.
• Case is carried. Color becomes Colour and COLOR becomes COLOUR.
• Identifiers are kept. A word in a domain, path, address or snake_case name (color.com, /center, color_scheme) keeps its spelling.
• Identity on no change. When nothing matches, the same string is returned, so you can compare by identity to skip a DOM write.

APICopy Anchor Link

• localiseSpelling(text, system) rewrites text into system ('british' | 'american' | 'canadian').
• spellingDictionary(system) returns the lowercase word map for a system, useful for style checks and tooling.

Australia, New Zealand, Ireland and most of the Commonwealth use 'british' (see Australian English).

Rewrite a page in the browserCopy Anchor Link

import { localiseSpelling, type SpellingSystem } from "@stunt-double/spelling";

function localisePage(root: Node, system: SpellingSystem): void {
  const walker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT);
  for (let node = walker.nextNode(); node; node = walker.nextNode()) {
    const text = node.nodeValue ?? "";
    const next = localiseSpelling(text, system);
    if (next !== text) node.nodeValue = next;
  }
}

Skip code, pre and anything else where text isn't prose.

Next stepsCopy Anchor Link

• Read the full API on GitHub