[ksa]

Как вариант...

const n = 10
const a = []
for (let i = 2; i <= n; i++) {
	let ok = true
	for (let j = 0; j < a.length; j++) {
		if (i % a[j] === 0) {
			ok = false
			break
		}
	}
	if (ok) a.push(i)
}
alert(a)