Simple linear regression implemented in JavaScript

simple-linear-regression.js

const inputArray = [
  {
    squareMeters: 200,
    priceInDollars: 190000
  },
  {
    squareMeters: 100,
    priceInDollars: 90000
  },
  {
    squareMeters: 115,
    priceInDollars: 120000
  },
  {
    squareMeters: 150,
    priceInDollars: 140000
  },
  {
    squareMeters: 140,
    priceInDollars: 125000
  }
];

function linearRegression(inputArray, xLabel, yLabel) {
  const x = inputArray.map((element) => element[xLabel]);
  const y = inputArray.map((element) => element[yLabel]);
  const sumX = x.reduce((prev, curr) => prev + curr, 0);
  const avgX = sumX / x.length;
  const xDifferencesToAverage = x.map((value) => avgX - value);
  const xDifferencesToAverageSquared = xDifferencesToAverage.map(
    (value) => value ** 2
  );
  const SSxx = xDifferencesToAverageSquared.reduce(
    (prev, curr) => prev + curr,
    0
  );
  const sumY = y.reduce((prev, curr) => prev + curr, 0);
  const avgY = sumY / y.length;
  const yDifferencesToAverage = y.map((value) => avgY - value);
  const xAndYDifferencesMultiplied = xDifferencesToAverage.map(
    (curr, index) => curr * yDifferencesToAverage[index]
  );
  const SSxy = xAndYDifferencesMultiplied.reduce(
    (prev, curr) => prev + curr,
    0
  );
  const slope = SSxy / SSxx;
  const intercept = avgY - slope * avgX;
  return (x) => intercept + slope * x;
}

const housePrice = linearRegression(inputArray, "squareMeters", "priceInDollars");

console.log(housePrice(100));
// => 94666.38513513515