index.js

#!/usr/bin/env node

console.log('yay gist');

var IntlMessageFormat = require('intl-messageformat');
var memoizeFormatConstructor = require('intl-format-cache');

IntlMessageFormat.defaultLocale = 'ru';

console.log(`Default locale BEFORE memoize: ${IntlMessageFormat.defaultLocale}`);

var memoizedIntlMessageFormat = memoizeFormatConstructor(IntlMessageFormat);
var msg = memoizedIntlMessageFormat('message');

console.log(`Locale used in memoized instance: ${msg._resolveLocale()}`);

package.json

{
  "name": "some-weird-gist-package",
  "bin": "./index.js",
  "version": "1.0.0",
  "dependencies": {
    "intl-format-cache": "^2.1.0",
    "intl-messageformat": "^2.2.0"
  }
}