How To Calculate Rate of Change (ROC) in JavaScript?

@connie.heaney 

Rate of Change (ROC) is a financial indicator that measures the rate at which a stock's price is changing over a specific period of time. To calculate ROC in JavaScript, you can use the following formula: ROC = ((Closing Price - Closing Price N periods ago) / Closing Price N periods ago) * 100

Here is a sample code snippet to calculate ROC in JavaScript:

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// Sample array of closing prices
const closingPrices = [100, 105, 110, 115, 120, 125, 130];

// Number of periods to calculate ROC
const n = 3;

function calculateROC(closingPrices, n) {
  const roc = [];

  for (let i = n; i < closingPrices.length; i++) {
    const currentPrice = closingPrices[i];
    const previousPrice = closingPrices[i - n];

    const rocValue = ((currentPrice - previousPrice) / previousPrice) * 100;
    roc.push(rocValue);
  }

  return roc;
}

const rocValues = calculateROC(closingPrices, n);
console.log(rocValues);

In this code snippet, we first define an array closingPrices that contains the closing prices of a stock over a period of time. We also define the number of periods n over which we want to calculate ROC.

We then define a function calculateROC that takes the closing prices array and number of periods as input parameters. Inside the function, we iterate over the closing prices array and calculate the ROC value for each period using the formula mentioned above. The calculated ROC values are then stored in an array and returned by the function.

Finally, we call the calculateROC function with the sample closing prices array and number of periods, and log the calculated ROC values to the console.

@connie.heaney 

The code snippet provided calculates the Rate of Change (ROC) for a given array of closing prices by applying the formula mentioned in the context.

To further clarify the steps involved in the code:

1. Define the array closingPrices containing the historical closing prices of a stock.
2. Specify the number of periods n over which you want to calculate the ROC.
3. Create a function calculateROC that takes the array of closing prices and the number of periods as arguments.
4. Iterate over the closing prices array, starting from the (n+1) element, as we need at least n periods of data for the calculation.
5. Calculate the ROC for each period using the formula and store the result in the roc array.
6. Return the array of ROC values.
7. Call the calculateROC function with the provided array of closing prices and the specified number of periods.
8. Log the calculated ROC values to the console for analysis.

By following these steps, the code effectively computes the Rate of Change (ROC) for the given stock closing prices data over the specified number of periods. This information can be valuable for evaluating the stock's price performance and identifying trends.