How to get value from array of objects?

You are trying to access properties of this.props.users before it has loaded. Your component renders without waiting for your data to fetch. When you console.log(this.props.users) you say that you get an array, but above that, it probably logs undefined at least once when the component renders before this.props.users has loaded.

You have a couple of options. You can either do this at the very top of your render method to prevent the rest of the code in the method from executing:

if (!this.props.users) return null;

Once the data is fetched and props change, the render method will be called again.

The other option is to declare a default value, of an empty array for users in your reducer.

Might be when you are executing that line this.props.users is undefined. Check the flow where you have added console.log(this.props.users[0])

const App = () => {
  
  const example = () => {
    const data =[{id:1 ,name: "Users1", description: "desc1"}, 
                {id:2 ,name: "Users2", description: "desc2"}];
    return (
      <div>
      {data.map(function(cValue, idx){
          console.log("currentValue.id:",cValue.id);
          console.log("currentValue.name:",cValue.name);
          console.log("currentValue.description:",cValue.description);
         return (<li key={idx}>name = {cValue.name} description = {cValue.description}</li>)
      })}
      </div>
      );
    }

  return(
    <p style = {{color:'white'}}>
      {example()}
    </p>
  );
}

export default App;