ES6 Newton Demo

gistfile1.js

"use strict"

const newton = ({
  f,
  df,
  initialGuess,
  tolerance = Number.EPSILON,
  maxIterations = 1000
}) => {
  let x = initialGuess;
  let iterations = 0;
  
  while (true) {
    let lastX = x;
    x -= f(x) / df(x);
    iterations++;
    
    let reachedTolerance = Math.abs(x - lastX) < tolerance;
    
    if (
      reachedTolerance ||
      iterations >= maxIterations
    ) {
      return [x, reachedTolerance];
    }
  }
};

let [sqrt2, success] = newton({
  f: x => x * x - 2,
  df: x => 2 * x,
  initialGuess: 17
});

console.log(sqrt2);