Draw triangle on JS Canvas

HTML

<canvas id="canvas" width="300" height="300"></canvas>

JavaScript

var canvasElement = document.querySelector("#canvas");
var ctx = canvasElement.getContext("2d");

// Sides: a = 30   b = 30   c = 59

var triangle = {
  x1: 30, 
  y1: 0, 
  x2: 0, 
  y2: 59, 
  x3: 30, 
  y3: 59 
}

ctx.strokeStyle = 'red';

ctx.beginPath();
ctx.moveTo(triangle.x1, triangle.y1);
ctx.lineTo(triangle.x2, triangle.y2);
ctx.lineTo(triangle.x3, triangle.y3);
ctx.lineTo(triangle.x1, triangle.y1);
ctx.closePath();
ctx.stroke();