Solution to Code VS Zombies challenge at https://www.codingame.com/ide/puzzle/code-vs-zombies.

CodeVSZombies.CodinGame.js

/**
 * Save humans, destroy zombies!
 * https://www.codingame.com/ide/puzzle/code-vs-zombies
 **/

const spartanSpeed = 1000;
const zombieSpeed = 400;
const killingDistance = 2000;
const speedDifferenceMultiplier = spartanSpeed / zombieSpeed;

const getDistance = (pointA, pointB) =>
  Math.hypot(pointA.x - pointB.x, pointA.y - pointB.y);

// game loop
while (true) {
  let humans = [];
  const zombies = [];

  const spartanCoordinates = readline().split(' ');
  const masterChief = {
    x: spartanCoordinates[0],
    y: spartanCoordinates[1],
    nextX: 0,
    nextY: 0
  };

  console.error('Master Chief 😎: ', masterChief);
  console.error(
    '************************** New Turn Starts ⚔️ ***************************'
  );

  const humanCount = parseInt(readline());
  for (let i = 0; i < humanCount; i++) {
    const inputs = readline().split(' ');
    const human = {
      id: parseInt(inputs[0]),
      x: parseInt(inputs[1]),
      y: parseInt(inputs[2]),
      distance: 0,
      alive: true
    };
    human.distance = getDistance(masterChief, human);
    humans.push(human);
  }
  humans = humans.sort((a, b) => a.distance - b.distance); // necessary?

  let ryan = null; // ryan or nemo?

  const zombieCount = parseInt(readline());
  for (let i = 0; i < zombieCount; i++) {
    const inputs = readline().split(' ');
    // if we already have a ryan/nemo, skip the rest of the zombies
    if (ryan) continue;
    const zombie = {
      id: parseInt(inputs[0]),
      x: parseInt(inputs[1]),
      y: parseInt(inputs[2]),
      nextX: parseInt(inputs[3]),
      nextY: parseInt(inputs[4])
    };
    console.error(`Zombie #${zombie.id} vs humans: `, zombie);
    // can Master Chief reach any of the humans before this zombie? find nemo!
    let ryans = humans.filter(h => {
      console.error('---');
      console.error('Human: ', h);
      const hDistance = getDistance(zombie, h);
      console.error('Distance (zombie to human): ', hDistance);
      const isSpartanCloser = h.distance - killingDistance < hDistance;
      console.error('Is Master Chief Closer?: ', isSpartanCloser);
      return isSpartanCloser;
    });
    console.error('Ryans: ', ryans);
    // any ryans so far?
    if (ryans.length > 0) {
      // found a ryan!
      ryans = ryans.sort((a, b) => a.distance - b.distance);
      console.error(`Ryans: `, ryans);
      ryan = ryans[0];
      console.error(
        '- Cortana: Master Chief, we found Nemo! 🚨 RESCUE RYAN! 🚨'
      );
      // (this metaphor is out of control... 😅)
    }

    zombies.push(zombie); // do I need to store zombies?
    console.error('-----------------------------------------');
  }

  const next = ryan || humans[0];
  masterChief.nextX = next.x;
  masterChief.nextY = next.y;

  // Write an action using console.log()
  // To debug: console.error('Debug messages...');

  console.log(`${masterChief.nextX} ${masterChief.nextY}`); // Your destination coordinates
}