Convert angle/magnitude to horizontal/vertical components (and back again)

JavaScript
1

[0, 0] is top left. 0 degrees is to the right, 270 is straight down.

I refer to angle as “direction”, magnitude as “speed”, and the horizontal and vertical components as “hspeed” and “vspeed”, respectively.

I have tried these 3 functions but they are all glitchy:

function velocityToSpeeds(direction, speed) {
  return {
    hspeed: Math.round(Number(-Number(speed)*Math.sin(Math.toRad(Number(direction) - 90)))) + 0, 
    vspeed: Math.round(Number(-Number(speed)*Math.cos(Math.toRad(Number(direction) - 90)))) + 0
  };
}

function velocityToSpeedsALTERNATIVE(direction, speed) {
  return {
    x: speed*Math.cos(Math.toRad(direction)), 
    y: speed*Math.sin(Math.toRad(direction))
  };
}

function speedsToVelocity(hspeed, vspeed) {
  return {
    direction: Math.round(Number(Math.toDeg(Math.atan2(Number(vspeed), Number(hspeed))))) + 0,
    speed: Math.round(Number(Math.sqrt(Number(hspeed) * Number(hspeed) + Number(vspeed) * Number(vspeed)))) + 0
  }
}`