chart = {
const svg = d3.select(DOM.svg(width, height))
.attr("id", "chart");
svg.append("g")
.attr("id", "x-axis")
.attr("transform", `translate(${margin.left}, ${height - margin.bottom})`)
.call(xaxis);
svg.append("g")
.attr("id", "y-axis")
.attr("transform", `translate(${margin.left}, ${margin.top})`)
.call(yaxis);
svg.append("g")
.attr("id", "bars")
.attr("transform", `translate(${margin.left}, ${margin.top})`)
.selectAll("rect")
.data(letters)
.enter()
.append("rect")
.attr("x", d => x(d.letter))
.attr("y", d => y(d.frequency))
.attr("width", x.bandwidth())
.attr("height", d => innerHeight - y(d.frequency));
return svg.node();
}