47 lines
1.4 KiB
TypeScript
47 lines
1.4 KiB
TypeScript
import { chain, pipe, sum } from "ramda";
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import { Interval } from "./ast";
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// Converts interval to array of intensity values for each second
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const intervalToIntensities = ({ duration, intensity }: Interval): number[] => {
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const seconds = [];
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const { from, to } = intensity;
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for (let i = 0; i < duration; i++) {
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// Intensity in a single second
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seconds.push(from + (to - from) * (i / duration));
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}
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return seconds;
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};
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// Starting at the beginning of the data, calculate 30-second rolling average
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const windowSize = 30;
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const rollingAverages = (intensities: number[]): number[] => {
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if (intensities.length < windowSize) {
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throw new Error(`Workout must be at least ${windowSize} seconds long`);
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}
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const averages: number[] = [];
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let rollingSum: number = sum(intensities.slice(0, windowSize));
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averages.push(rollingSum / windowSize);
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for (let i = 0; i < intensities.length - windowSize; i++) {
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rollingSum -= intensities[i];
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rollingSum += intensities[i + windowSize];
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averages.push(rollingSum / windowSize);
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}
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return averages;
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};
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const fourthPower = (x: number) => Math.pow(x, 4);
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const fourthRoot = (x: number) => Math.pow(x, 1 / 4);
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const average = (arr: number[]) => sum(arr) / arr.length;
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export const normalizedIntensity = (intervals: Interval[]): number => {
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return pipe(
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chain(intervalToIntensities),
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rollingAverages,
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(averages) => averages.map(fourthPower),
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average,
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fourthRoot
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)(intervals);
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};
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