setState from json object gives undefined [React]

Question

So i got this problem where i get an response from my backend and i parse it to json then call my set function like this

try{
    const leaderboardInfo: LeaderboardState = JSON.parse(response);
    this.onLeaderboardStateUpdate(leaderboardInfo);
    console.log(leaderboardInfo);
}
catch(e){
    console.log(`Failed to convert: ${response} into a JS object`);
}

And the console.log gives me this response

So so far so good its the LeaderboardConfig that i want to use to set the state.

My setState function is just an basic one

onLeaderboardStateUpdate(state: LeaderboardState): void
{
    this.setState({leaderboardState: state})
}

and my state looks like this

this.state = {
    leaderboardState: {LeaderboardId: 0,LeaderboardName:"",StartDate:"",EndDate: ""}
};

but for some reason this gives undefined so it seems not be able to setState from the json object i have

for your information as well leaderboardState is an interface which looks like this.

export interface LeaderboardState {
    LeaderboardId: number
    LeaderboardName: string
    StartDate: string
    EndDate: string
}

What Jai said made me solve it i had to change the try catch to this

try{
    const leaderboardInfo = JSON.parse(response);
    this.onLeaderboardStateUpdate(leaderboardInfo.LeaderboardConfig[0]);
    console.log(leaderboardInfo);
        }
        catch(e)
        {
            console.log(`Failed to convert: ${response} into a JS object`);
        }

Removing the LeaderboardState interface here and going into LeaderBoardConfiguration which when i had the interface in there messed up.

Please provide the full error log. Also recheck the method bindings with this as Matthi said — Parnab Sanyal
– Parnab Sanyal, Commented Nov 12, 2018 at 10:07

Jai · Accepted Answer · 2018-11-12 09:59:28Z

2

I suppose you have to send the object instead of array:

this.onLeaderboardStateUpdate(leaderboardInfo[0]); 
// [0] will extract the object inside array.-^^^

answered Nov 12, 2018 at 9:59

Jai

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