How to solve the typescript error hint?

[ShangChien]

This question is not directly related with the VUEUSE theme, but the open source comminication here is more active, so I like to ask it here:
this code logic is self-consistent, and i don't like to use any .

const initArray:molData[]=Array.from(Array(100),(v,i)=>{
  let seed=i%6
  if (seed===0){
    return mol1
  }else if (seed===1){
    return mol2
  }else if (seed===2){
    return mol3
  }else if (seed===3){  
    return mol4
  }else if (seed===4){
    return mol5
  }else if (seed===5){
    return mol6
  }
});

thank you !!
hope solution

[ShangChien]

if (...){
  return ...
}else if (...){
  return ...
}else{
  return ...

seems the loop must be complete, end with else