Standard Deviation in JS

stdDeviation.js

function stdDeviation(input, isAmostra){
	let amostral = 0;
	if(isAmostra != null) amostral = 1;
	let sum = input.reduce((acc,val) => acc+val);
	let mean = sum/input.length;
	let diff2 = input.map(val => Math.pow(val - mean,2));
	let sumDiff = diff2.reduce((acc,val) => acc+val);
	let desv = Math.sqrt(sumDiff/(input.length-amostral));
	console.log(mean);
	console.log(desv);
}

stdDeviation([14,15,9,1],true);