index parameter is not reset for every iteration

[nagarajanchinnasamy]

As per the below example code:

const MoveStuffAround = () => (
    <Ticker>
        {({ index }) => (
            <>
                <h1>This is the Headline of element #{index}!</h1>
                <img src="www.my-image-source.com/" alt=""/>
            </>
        )}
    </Ticker>
)

I expected that the index value will be reset based on the number of children elements inside <Ticker>.

However, it seems to be a continuous counter value irrespective of the number of children. Because of this, after the first iteration through all messages, it goes out of bound of messages array - if one keeps messages in an array and use the index.

Either code should be fixed. Otherwise, the documentation needs to be fixed :)

[nagarajanchinnasamy]

The code I have:

// Notice the need for modulus operator
const getMessage = i => {
    const messages = [
        "message-0",
        "message-1",
        "message-2",
    ]
   console.log("Value of i is: " + i%messages.length)
   return (
       <>
           <div style={{ marginRight: "1rem" }}>
               <p style={{ whiteSpace: "nowrap", color: "#e83e0a" }}>
                   {messages[i%messages.length]}
               </p>
           </div>
       </>)
}

<Ticker mode="await" move={true}>
    {({index}) => getMessage(index)}
</Ticker>

[praveen-ranjan-ocl]

Hi, Did you get any solution?

[AndreasFaust]

You are right: index is a continuous counter, which has no relation to the elements itself. It just counts the event, react-ticker orders a new element. This is not mentioned in the docs so far, which needs to be changed.

[praveen-ranjan-ocl]

I wrote a method that returns only one item from the list at a time. Used state to check and reset if list reach to last element. See my solution here:

import React, { useState } from "react";
import Ticker from "react-ticker";
import PropTypes from "prop-types";

const TickerComponent = props => {
const [count, setCount] = useState(0);
const getNewsItem = () => {
if (count < props.data.length - 1) {
console.log("befor calling setCount ", count);
setCount(count + 1);
console.log("count after::", count);
} else {
setCount(0);
}
const item = props.data[count];

return (
  <>
   
    <span>
      {item.Description + " count::" + count}
    </span>
  </>
);

};

return (

{() => getNewsItem()}

);
};

TickerComponent.propTypes = {
data: PropTypes.array
};

export default TickerComponent;

[Sayak-0512]

I don't have an elegant way to solve this, but I have found a way to solve the issue.

const post=[1,2,3,4,5]; function Outpu(){ return <Ticker height={120} speed={20} > {({ index }) => ( <> <div style={{display: "none"}}> {index=index%posts.length} </div> <div> Your content here. </div> </> )} </Ticker>
}