Run results for: Ways to cache Intl.NumberFormat

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.0.1 Safari/605.1.15

Browser: Safari 26

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 6 months ago

Test name	Executions per second
Always new instance	28431.7 Ops/sec
static global instance	1584848.4 Ops/sec
Lodash cache	1044699.2 Ops/sec
Custom cache with maps	1681499.9 Ops/sec
Custom cache with objects	1484761.0 Ops/sec

HTML Preparation code:

<script src='https://cdn.jsdelivr.net/npm/lodash@4.17.21/lodash.min.js'></script>

Script Preparation code:

const formatOptions = {
  minimumFractionDigits: 0,
  maximumFractionDigits: 0,
  useGrouping: false,
  style: 'percent',
};

const staticInstanceDe = new Intl.NumberFormat("de", formatOptions);
const staticInstanceFr = new Intl.NumberFormat("fr", formatOptions);

const lodashCache = _.memoize(
    (locale, options) => new Intl.NumberFormat(locale, options),
    (locale, options) => `${locale}-${JSON.stringify(options)}`,
);

const mapCache = new Map();
const getMapCacheInstance = (locale, options) => {
  let lang;
  if (!mapCache.has(locale)) {
    lang = new Map();
    mapCache.set(locale, lang);
  } else {
    lang = mapCache.get(locale);
  }
  if (!lang.has(options)) {
    const newInstance = new Intl.NumberFormat(locale, options);
    lang.set(options, newInstance);
    return newInstance;
  }
  return lang.get(options);
}

const objCache = {};
const getObjCacheInstance = (locale, options) => {
  let lang = objCache[locale];
  if (!lang) {
    lang = {};
    objCache[locale] = lang;
  }
  if (!lang[options]) {
    const newInstance = new Intl.NumberFormat(locale, options);
    lang[options] = newInstance;
    return newInstance;
  }
  return lang[options];
}

Tests:

Always new instance
new Intl.NumberFormat("de", formatOptions).format(0.123) new Intl.NumberFormat("fr", formatOptions).format(0.123)
static global instance
staticInstanceDe.format(0.123) staticInstanceFr.format(0.123)
Lodash cache
lodashCache("de", formatOptions).format(0.123) lodashCache("fr", formatOptions).format(0.123)
Custom cache with maps
getMapCacheInstance("de", formatOptions).format(0.123) getMapCacheInstance("fr", formatOptions).format(0.123)
Custom cache with objects
getObjCacheInstance("de", formatOptions).format(0.123) getObjCacheInstance("fr", formatOptions).format(0.123)

Run results for: Ways to cache Intl.NumberFormat

Try to test different ways of keeping Intl.NumberFormat instances for better performance.

Always new instance

static global instance

Lodash cache

Custom cache with maps

Custom cache with objects