Edit in JSFiddle

// Get random number from 31 to 49 [Lodash]

// Utility method
function getRandomNumber(min, max) {
	return Math.floor(Math.random() * (max - min + 1)) + min;
}

var pureJS = getRandomNumber(31, 49);

// Lodash
var lodash = _.random(31, 49);

console.log(pureJS); // 34
console.log(lodash); // 32