Understanding barstate.isconfirmed Function in Pine Script

In this article, we delve into the functionality and application of barstate.isconfirmed in Pine Script, particularly in the context of plotting a Relative Strength Index (RSI) indicator. We’ll explore how this feature helps in managing the peculiarities of real-time versus historical data in trading scripts.

What is barstate.isconfirmed?

barstate.isconfirmed is a built-in boolean variable in Pine Script. Its primary purpose is to differentiate between historical and real-time bars in a chart.

• Historical Bars: For all historical bars, barstate.isconfirmed is always true. This means that the data for these bars is finalized.
• Real-Time Bars: For the real-time bar, barstate.isconfirmed becomes true only when the bar closes. This is critical to avoid what is known as ‘repainting’ – a situation where an indicator changes its values as new price data comes in.

Application in Plotting RSI

Now, let’s apply this to plot a Relative Strength Index (RSI), ensuring that it only plots on confirmed bars to avoid repainting:

Pine Script Example:

//@version=5
indicator("My Unique RSI Indicator",overlay = true)
customRSI = ta.rsi(close, 20)
plot(barstate.isconfirmed ? customRSI : na)

Breakdown of the Script:

1. indicator("My Unique RSI Indicator"): This line initializes our custom indicator and names it “My Unique RSI Indicator”.
2. customRSI = ta.rsi(close, 20): We declare a variable customRSI and assign it the value of the RSI computed over the last 20 bars. ta.rsi() is a built-in function that calculates the RSI.
3. plot(barstate.isconfirmed ? customRSI : na): This is where barstate.isconfirmed comes into play. We use a ternary operator to decide what to plot:
   • If barstate.isconfirmed is true (i.e., for historical bars and the last update of a real-time bar), we plot customRSI.
   • If barstate.isconfirmed is false (i.e., during the formation of a real-time bar), we plot na (not available), essentially plotting nothing.

Key Features and Takeaways:

• Function Usability: barstate.isconfirmed is highly useful for strategies and indicators that need to avoid repainting, ensuring decisions are based on confirmed data.
• Syntax: The syntax is straightforward, often used in conditional statements to determine whether to execute certain code segments.
• Application: Particularly useful in time-sensitive indicators like RSI, where real-time data might cause misleading signals if not handled properly.
• Limitation: It’s important to note that barstate.isconfirmed does not work within request.security() calls, which are used to fetch data from different timeframes or symbols.

In conclusion, barstate.isconfirmed is a valuable tool in Pine Script programming, particularly for ensuring accuracy and reliability in indicators and strategies that rely on real-time data. By understanding and applying this function correctly, traders and programmers can significantly enhance the effectiveness of their trading scripts.