var data_set = [
  [0,1],
  [1,3],
  [2,5],
  [3,7],
  [4,9]
];

var w = -10054;
var b = 1;
var lr = 0.1;

function step(point){
  console.log(w);
  let dy = point[1];
  let y = w*point[0]+b;
  let err = dy-y;
  w += lr*(dy-y); //!! THE ADJUSTMENT WHICH MAKES w CONVERGE TO CORRECT VAL
};

console.clear();
for(var i = 0; i < 20; i++)
  for(var j = 0; j < data_set.length; j++)
    step(data_set[j]);

console.log(w);
console.log(w*3+b)