Localize English spelling

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

InstallCopy Anchor Link

Until the @stunt-double scope is available on npm, 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'.

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