Survivor.js

function kill(people) {
  const survivors = [];
  for(let i =0; i < people.length; i++) {
      if (i % 2 === 0) { // index start from 0, so odd is even
        console.log("a person is killed");
        // then do nothing
      }
      else {
    	  survivors.push(people[i]);
        // Or add to new line;
      }
  }
  return survivors;
}

var people = [];

// Make 100 people
for (let i = 1 ; i <= 100; i++) {
  people.push(i);
}

console.log(people);

while (people.length > 1) {
  people = kill(people);
  console.log(people);
}