How to find the coordinate that is closest to the point of origin?

arrays, coordinate-systems, coordinates, google-maps, javascript

Solution

Calculate the distance of each point using

Math.sqrt( Math.pow(x, 2) + Math.pow(y, 2) );

Take the result that's the lowest

var points = [
  {x: 10, y: 20},
  {x: 12, y: 18},
  {x: 20, y: 30},
  {x: 5, y: 40},
  {x: 100, y: 2}
];

function d(point) {
  return Math.pow(point.x, 2) + Math.pow(point.y, 2);
}

var closest = points.slice(1).reduce(function(min, p) {
  if (d(p) < min.d) min.point = p;
  return min;
}, {point: points[0], d:d(points[0])}).point;

closest;
// {x: 12, y:18}

You'll notice that we're skipping the `Math.sqrt` step here. As Mark Setchell points out, calculating the square root is a sort of "lowest common denominator" operation; We can still determine the closest point by getting the smallest `x^2 + y^2` value.

Problem

I know there are many many questions about sorting javascript arrays by multiple values, but none of the answers solved my problem. I have an array of coordinates like: ``` x | y -------- 10 20 12 18 20 30 5 40 100 2 ``` How can I get the coordinate that is closest to the point of origin?

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