verlet.js

function verlet(pos, acc, dt) {
  let prevPos = pos;
  let time = 0;
  let tempPos;

  while (pos > 0) {
    time += dt;
    tempPos = pos;
    pos = pos * 2 - prevPos + acc * dt * dt;
    prevPos = tempPos;
  }

  return time;
}

function stormerVerlet(pos, acc, dt) {
  let prevPos = pos;
  let time = 0;
  let vel = 0;
  let tempPos;

  while (pos > 0) {
    time += dt;
    tempPos = pos;
    pos = pos * 2 - prevPos + acc * dt * dt;
    prevPos = tempPos;

    vel += acc * dt;
  }

  return { time, vel };
}

function velocityVerlet(pos, acc, dt) {
  let time = 0;
  let vel = 0;

  while (pos > 0) {
    time += dt;
    pos += vel * dt + 0.5 * acc * dt * dt;
    vel += acc * dt;
  }

  return { time, vel };
}

const time = verlet(5, -10, 0.01);
console.log(`[#] Time for Verlet integration is:`);
console.log(`${time}`);

const stormer = stormerVerlet(5, -10, 0.01);
console.log(`[#] Time for Stormer Verlet integration is:`);
console.log(`${stormer.time}`);
console.log(`[#] Velocity for Stormer Verlet integration is:`);
console.log(`${stormer.vel}`);

const velocity = velocityVerlet(5, -10, 0.01);
console.log(`[#] Time for velocity Verlet integration is:`);
console.log(`${velocity.time}`);
console.log(`[#] Velocity for velocity Verlet integration is:`);
console.log(`${velocity.vel}`);