Fetch resources lazily - either whenever the browser is next idle, or when you request the resource.

In a browser that doesn't have requestIdleTimeout, or in node.js, falls back to setTimeout(fn, 1000).

Inspired directly by this 💯 post by Philip Walton, but uses a function-based API instead of classes. It's also about a third the size of idlize/defineIdleProperty.mjs (after minification) by avoiding classes and using the dumbest possible requestIdleTimeout fallback.

npm i idle-until-urgent

const makeIdleGetter = require('idle-until-urgent')

const getFormatter = makeIdleGetter(() => new Intl.DateTimeFormat('en-US', {
	timeZone: 'America/Los_Angeles',
}))

// later in your code, presumably not during the first tick...

getFormatter().format(new Date(1537452915210)) // => '9/20/2018'

WTFPL