How to convert RR (IBI) data to Heart Rate in Javascript

Question

after doing a some research I reached the point that I decided to ask here for advice as I am not sure how to proceeed.

The problem:

I have an array of RR (IBI) data

Example: [679, 686, 650...]

How can I convert this to heart rate?

My research:

• http://www.meddean.luc.edu/lumen/meded/medicine/skills/ekg/les1prnt.htm
• Vairous libs on github but none on JS or in a way I could port to JS
-

My approach which of course is defective:

for (const ibiInMilliseconds of eventJSONObject.DeviceLog["R-R"].Data) {
      ibiBuffer.push(ibiInMilliseconds);
      const ibiBufferTotal = ibiBuffer.reduce((a, b) => a + b, 0);
      // If adding the ibi to the start of the activity is greater or equal to 2.5 second then empty the buffer there
      if ((lastDate.getTime() + ibiBufferTotal) >= lastDate.getTime() + 2500) {
        const average = ibiBuffer.reduce((total, ibi) => {
          return total + ibi;
        }) / ibiBuffer.length;

        const avg = 1000 * 60 / average; 
        // I save this avg to a 1s list but it's very error prone


        ibiBuffer = [];
        lastDate = new Date(lastDate.getTime() + ibiBufferTotal);
      }
    }

I would appreciate any kind of help or pointers as where to look.

Answer 1

After a lot of time testing etc the correct answer is:

/** 
   * Converts the RR array to HR instantaneus (what user sees) 
   * @param rrData 
   * @return {any} 
   */ 
  public static convertRRtoHR(rrData): Map<number, number> { 
    let totalTime = 0; 
    return rrData.reduce((hrDataMap: Map<number, number>, rr) => { 
      totalTime += rr; 
      hrDataMap.set(totalTime, Math.round(60000 / rr)); 
      return hrDataMap; 
    }, new Map()); 
  }