How to compute the distance between two Cartesian points in JavaScript

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, updated (originally posted )

Given two Cartesian coordinates, here’s how you compute the distance between them:

function pointDistance(x1, y1, x2, y2) {
  return Math.hypot(x1 - x2, y1 - y2);
}

Here’s how you might use this function:

pointDistance(0, 0, 3, 4);
// => 5

pointDistance(100, 7, 200, 7);
// => 100

Supporting ancient browsers

The above solution uses Math.hypot(), which has been supported in browsers since around 2014. If you need to support ancient browsers that don’t have Math.hypot(), you can use Math.sqrt() which has been around for a long time.

// This version supports very old browsers.
function pointDistance(x1, y1, x2, y2) {
  var dx = x1 - x2;
  var dy = y1 - y2;
  return Math.sqrt(dx * dx + dy * dy);
}

It’s used the same way.