how to create state array react hooks on declaration

Question

How do I create a state array with react hooks? I am passing a Type I used this method but it's showing me lint error. I also want to know it's the correct method

const [myList, setList] = React.useState<IList[]>([
  {
    ID: 1,
    Lname: "R1",
    LType: 1
  },
  {
    ID: 2,
    Lname: "R4",
    LType: 5
  }
]);

And my type looks like

interface IList {
  ID: number;
  Lname: string;
  LType: number;
}

Please add the lint error text!

Nick
– Nick

2019-11-16 16:12:01 +00:00
Commented Nov 16, 2019 at 16:12 — Nick
– Nick, Commented Nov 16, 2019 at 16:12

Nick · Accepted Answer · 2019-11-16 16:19:54Z

2

You just need to tell it it's an array of objects. Here's a codesandbox example of this typing working now.

const [myList, setList] = React.useState<IList[]>([
        {
            ID: 1,
            Lname: "R1",
            LType: 1
        }, {
            ID: 2,
            Lname: "R4",
            LType: 5
        }])

edited Nov 16, 2019 at 16:19

answered Nov 16, 2019 at 15:40

Nick

16.7k3 gold badges21 silver badges38 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Ankit Jayaprakash Over a year ago

I passed like that only. i forget to mention. still its showing lint

Ankit Jayaprakash Over a year ago

Argument of type '({ ID: number; Lname: string; LType: number; } | { ID: number; Lname: string; LType: number; })[]' is not assignable to parameter of type 'IList | (() => IList)'.

Nick Over a year ago

At this point, I suspect the issue is actually where you're using setList somewhere else in the app.

Nick Over a year ago

Here's an example of that typing working just fine codesandbox.io/s/cool-galois-j8lvw

Ankit Jayaprakash Over a year ago

I tried by changing the name. But still its showing the same. And @Nick you great, with give an example. thank you.

dave brudner · Accepted Answer · 2019-11-16 15:42:00Z

1

It looks like you're passing in the wrong type for state. Instead of IList, it looks like it should be IList[]

If you're still seeing errors, it might be useful to share them.

answered Nov 16, 2019 at 15:42

dave brudner

312 bronze badges

Collectives™ on Stack Overflow

how to create state array react hooks on declaration

2 Answers 2

5 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

5 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related