Reduce : Last two

	let value = 610;
	const table = new Map([
	[0,'yellowgreen'],
	[150, 'green'],
	[600, 'olive'],
	[750, 'red'],
	[800, 'black'],
	]);
	const closestKey = [...table.keys()].reduce( (acc, key) => {
	return acc = ( Math.abs(acc-value) < Math.abs(key-value) ) ? acc : key
	})
	console.log(`the closest value of ${value} is ${table.get(closestKey)}`)

view raw closest.js hosted with ❤ by GitHub

	const country = new Map([
	["france","Fr"],["bresil","Br"],["argentine","Ar"],["senegal","Se"],
	]);
	const objCountry = Object.fromEntries(country);
	const reverseMapping = o => Object.keys(o).reduce((a, k) =>
	Object.assign(a, { [o[k]]: k }), {})
	const T = new Map(Object.entries(reverseMapping(objCountry)));
	console.log(T.get("Br"))

view raw reverseMapping.js hosted with ❤ by GitHub