Ошибка TypeError: canvas.getContext is not a function
// не изменять
$(`.stat`).append(`<div data-type="volume"><div>`);
let elem = $(`.stat [data-type="volume"]`);
// не изменять
let canvas = elem.html('<canvas></canvas>').find('canvas');
let ctx = canvas.getContext('2d');
let width = canvas.offsetWidth * 2;
let height = canvas.offsetHeight * 2;
console.log(canvas, width, height);
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="stat"></div>
Источник: Stack Overflow на русском