JSFiddle - React, Tailwind, and code Playground

by asdf

JavaScript

// 1. Find all prime numbers in range 1..n
// 1,3,5,7,11,13,17,19.... <= n

function getAllPrime(n) {
	var res = [];
  var arr = [];
  for (var i=1; i<3; i++) {
  	if (i<=n) {
    	res.push(i);
    }
  }
  for (var j=3; j<=n; j+=2) {
  	if (arr[j] === undefined) {
    	arr[j] = true;
    }
    arr[j] && res.push(j);
    for (var k=j*j; k<=n; k+=j) {
    	arr[k] = false;
    }
  }
  return res;
}
console.log(getAllPrime(15));
console.log(getAllPrime(50));