Pi Calculation With JavaScript

pi.js

// low perf
const fn = n => Math.pow(-1, n)/(2*n + 1);
const sum = (a, b) => a + b;

const range = (n) => {
    let i = 0;
    let numbers = [];
    while(i < n) {
        numbers.push(i);
        i++;
    };
    return numbers;
}

const pi = 4 * range(10000).map(fn).reduce(sum);

// medium perf
const piRange = (n) => {
    let i = 0;
    let numbers = [];
    while(i < n) {
        numbers.push(fn(i));
        i++;
    };
    return numbers;
}

const pi = 4 * piRange(10000000).reduce(sum);

// good perf
const piSum = (n, i, a) => {
    let i = 0;
    let sum = 0;
    while(i < n) {
        sum += fn(i)
        i++;
    };
    return sum;
}

const piSumR = (n, i=0, a=0) => {
    if(i === n) {
        return a;
    }
    return piSum(n, i+1, a+fn(i));
}

const pi = 4 * piSum(20);