A fast algorithm for computing the n-th number in the fibonacci series in Node.js

fib.js

const N = 1000000

function fib(nth) {
    if (nth < 3) {
        return 1n
    }
    let a = b = 1n, c
    for (let i = 3; i <= nth; i++) {
        c = a + b
        a = b, b = c
    }
    return c
}

console.time('computing')
const result = fib(N)
console.timeEnd('computing')
console.log(`Fibonacci #${N} = ${result}\n${result.toString().length} digits`)