@netdata/charts/dist/es6/helpers/canvas/index.test.js

Netdata frontend SDK and chart utilities

import { createCanvas, copyCanvas } from ".";
it("#createCanvas creates a canvas with the given width and height", function () {
  var canvas = createCanvas(100, 200);
  expect(canvas.width).toBe(100);
  expect(canvas.height).toBe(200);
});

// it("#copyCanvas copies the source canvas to the target canvas", () => {
//   const sourceCanvas = createCanvas(100, 200)
//   const sourceCtx = sourceCanvas.getContext("2d")
//   sourceCtx.fillStyle = "red"
//   sourceCtx.fillRect(0, 0, 100, 200)

//   const targetCanvas = createCanvas(100, 200)
//   copyCanvas(sourceCanvas, targetCanvas)

//   const targetCtx = targetCanvas.getContext("2d")
//   const imageData = targetCtx.getImageData(0, 0, 100, 200).data

//   expect(imageData).toEqual(new Uint8ClampedArray(100 * 200 * 4).fill(255))
// })