function hideControls()

in src/playground.ts [1027:1065]
35 lines of code
3 McCabe index (conditional complexity)

function hideControls() {
  // Set display:none to all the UI elements that are hidden.
  let hiddenProps = state.getHiddenProps();
  hiddenProps.forEach(prop => {
    let controls = d3.selectAll(`.ui-${prop}`);
    if (controls.size() === 0) {
      console.warn(`0 html elements found with class .ui-${prop}`);
    }
    controls.style("display", "none");
  });

  // Also add checkbox for each hidable control in the "use it in classrom"
  // section.
  let hideControls = d3.select(".hide-controls");
  HIDABLE_CONTROLS.forEach(([text, id]) => {
    let label = hideControls.append("label")
      .attr("class", "mdl-checkbox mdl-js-checkbox mdl-js-ripple-effect");
    let input = label.append("input")
      .attr({
        type: "checkbox",
        class: "mdl-checkbox__input",
      });
    if (hiddenProps.indexOf(id) === -1) {
      input.attr("checked", "true");
    }
    input.on("change", function() {
      state.setHideProperty(id, !this.checked);
      state.serialize();
      userHasInteracted();
      d3.select(".hide-controls-link")
        .attr("href", window.location.href);
    });
    label.append("span")
      .attr("class", "mdl-checkbox__label label")
      .text(text);
  });
  d3.select(".hide-controls-link")
    .attr("href", window.location.href);
}