storybook-addon-measure-viewport/dist/esm/preset/manager.js

Measures the height and width of the current viewport

import { addons, types } from "@storybook/addons";
import { ADDON_ID, TOOL_ID } from "../constants";
import { Tool } from "../Tool"; // Register the addon

addons.register(ADDON_ID, function () {
  // Register the tool
  addons.add(TOOL_ID, {
    type: types.TOOL,
    title: "Measure Viewport",
    match: function match(_ref) {
      var viewMode = _ref.viewMode;
      return !!(viewMode && viewMode.match(/^(story|docs)$/));
    },
    render: Tool
  });
});