add helpers

Author: desher

src/helpers/calc.ts

@@ -0,0 +1,11 @@
+export const calculateMean = (values: number[]) => values.reduce((acc, val) => acc + val, 0) / values.length;
+
+export const calculateVolatility = (values: number[]) => {
+  if (values.length === 0) {
+    throw new Error('Cannot calculate volatility for empty array');
+  }
+
+  const mean = calculateMean(values);
+  const meanAbsoluteDeviationFps = values.reduce((acc, val) => acc + Math.abs(val - mean), 0) / values.length;
+  return (meanAbsoluteDeviationFps * 100) / mean;
+};