Bar graph added.

node_modules/d3-format/src/precisionRound.js

@@ -0,0 +1,6 @@
+import exponent from "./exponent.js";
+
+export default function(step, max) {
+  step = Math.abs(step), max = Math.abs(max) - step;
+  return Math.max(0, exponent(max) - exponent(step)) + 1;
+}