Theo's Typesafe Cult•2y ago

How to use useQuery...?

Uber noob question here, I seem to have a misunderstanding of useQuery. Here is all im trying to do - use it to return an array from my database, console log the data. Here is my component, when it loads it doesn't log anything (because getAllCars.data hasn't resolved yet?), as if I need to await the data (what is the pattern for this in TRPC?). If I wasn't using TRPC, I would have the cars data set to a state so I can put the loop inside a useEffect with cars state as a dependancy, however I understand the TRPC patterns are different. Looking at the useQuery docs, the useQuery example doesn't help. The data just seems to be there? Anyway the solution is presumably. very simple, hoping someone can point me in the right direction

const AddPart: React.FC<AddPartProps> = () => {

  const getAllCars = trpc.cars.getAll.useQuery();
  const savePart = trpc.parts.createPart.useMutation();

  useEffect(() => {
    getAllCars.data?.forEach((car: ICar) => {
      console.log(car.make)
    });

  }, []);


  return (
      <div>Test</div>
  )
    export default AddPart

const AddPart: React.FC<AddPartProps> = () => {

  const getAllCars = trpc.cars.getAll.useQuery();
  const savePart = trpc.parts.createPart.useMutation();

  useEffect(() => {
    getAllCars.data?.forEach((car: ICar) => {
      console.log(car.make)
    });

  }, []);


  return (
      <div>Test</div>
  )
    export default AddPart

8 Replies

Unknown User•2y ago

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cornflour•2y ago

useQuery is a hook, not a function and it itself already returns the data

const AddPart: React.FC<AddPartProps> = () => {
  // no need to define type here since it's already inferred from the return type of the backend function
  const {data: cars} = trpc.cars.getAll.useQuery()
  console.log(cars)
}

const AddPart: React.FC<AddPartProps> = () => {
  // no need to define type here since it's already inferred from the return type of the backend function
  const {data: cars} = trpc.cars.getAll.useQuery()
  console.log(cars)
}

Cody•2y ago

Ugh, for some reason I thought only state could be used in a dep array. Like a thought, simple solution. Thankyou so much!

cornflour•2y ago

wait i misread the code fuck sorry yea just simple dep stuff

Cody•2y ago

No problem! Appreciate the response

cornflour•2y ago

i do wonder if the useEffect is necessary at all though

Unknown User•2y ago

Message Not Public

barry•2y ago

It's not data is state

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How to use useQuery...?