intl-plural-rules-polyfill

A simple Intl.PluralRules polyfill. Can be imported as "cardinals"-only. Created as part of relative-time-format.

Install

npm install intl-plural-rules-polyfill --save

If you're not using a bundler then use a standalone version from a CDN.

Use

import PluralRules from "intl-plural-rules-polyfill"

const pluralRules = new PluralRules("en", {
  style: "cardinal" // "cardinal" is the default. Other options: "ordinal".
})

pluralRules.select(0) // "other"
pluralRules.select(1) // "one"

The possible return values are:

• zero
• one
• two
• few
• many
• other

For more info on which is which read the official Unicode CLDR documentation. Unicode CLDR (Common Locale Data Repository) is an industry standard and is basically a collection of formatting rules for all locales (date, time, currency, measurement units, numbers, etc).

Cardinals

If the app only uses "cardinals" type and doesn't use "ordinals" then the polyfill can be imported as "cardinals"-only.

import PluralRules from "intl-plural-rules-polyfill/cardinal"

Under the hood

To determine whether a number is one, few, or something else, this polyfill uses Unicode CLDR rules for formatting plurals compiled into javascript by make-plural. These rules are number quantifying functions (one for each locale) which can tell if a number should be treated as zero, one, two, few, many or other. Knowing how these pluralization rules work is not required but anyway here are some links for curious advanced readers: rules explanation, list of rules for all locales, list of rules for all locales in JSON format (part of cldr-core/supplemental package), converting those rules to javascript functions.

Plural rule functions (./source/ordinals.js and ./source/cardinals.js) are generated by running:

npm install make-plural@latest --save-dev
npm run generate

CDN

One can use any npm CDN service, e.g. unpkg.com or jsdelivr.net

<script src="https://unpkg.com/intl-plural-rules-polyfill@[version]/bundle/polyfill.js"></script>

<script>
  new PluralRules('en').select(0)
</script>

where [version] is an npm package version range (for example, 0.2.x or ^0.2.0).

License

MIT