Looker Custom Visualization

Question

I want to make a custom visualization which will add the values of two measure from the first row and display the value .For this I have been using the HelloWorld code provided by looker itself by making just few changes(text in Red).But I am not able to get the expected result, it just gives output as Undefined.

Here’s my code:-

looker.plugins.visualizations.add({
  // Id and Label are legacy properties that no longer have any function besides documenting
  // what the visualization used to have. The properties are now set via the manifest
  // form within the admin/visualizations page of Looker
  id: "hello_world",
  label: "Hello World",
  options: {
    font_size: {
      type: "string",
      label: "Font Size",
      values: [
        {"Large": "large"},
        {"Small": "small"}
      ],
      display: "radio",
      default: "large"
    }
  },
  // Set up the initial state of the visualization
  create: function(element, config) {

    // Insert a <style> tag with some styles we'll use later.
    element.innerHTML = `
      <style>
        .hello-world-vis {
          /* Vertical centering */
          height: 100%;
          display: flex;
          flex-direction: column;
          justify-content: center;
          text-align: center;
        }
        .hello-world-text-large {
          font-size: 72px;
        }
        .hello-world-text-small {
          font-size: 18px;
        }
      </style>
    `;

    // Create a container element to let us center the text.
    var container = element.appendChild(document.createElement("div"));
    container.className = "hello-world-vis";

    // Create an element to contain the text.
    this._textElement = container.appendChild(document.createElement("div"));

  },
  // Render in response to the data or settings changing
  updateAsync: function(data, element, config, queryResponse, details, done) {

    // Clear any errors from previous updates
    this.clearErrors();

    // Throw some errors and exit if the shape of the data isn't what this chart needs
    if (queryResponse.fields.dimensions.length == 0) {
      this.addError({title: "No Dimensions", message: "This chart requires dimensions."});
      return;
    }

    // Grab the first cell of the data
    var firstRow = data[0];
    var secondRow = data[0];
    var firstCell = firstRow[queryResponse.fields.measures[0].name];
    var secondCell =secondRow[queryResponse.fields.measures[1].name];
    var totalSat = firstCell+secondCell;

    // Insert the data into the page
    this._textElement.innerHTML = LookerCharts.Utils.htmlForCell(totalSat);

    // Set the size to the user-selected size
    if (config.font_size == "small") {
      this._textElement.className = "hello-world-text-small";
    } else {
      this._textElement.className = "hello-world-text-large";
    }

    // We are done rendering! Let Looker know.
    done()
  }
});

Answer 1

This is almost perfect! The issue lies in these lines:

    var firstCell = firstRow[queryResponse.fields.measures[0].name];
    var secondCell =secondRow[queryResponse.fields.measures[1].name];
    var totalSat = firstCell+secondCell;

    // Insert the data into the page
    this._textElement.innerHTML = LookerCharts.Utils.htmlForCell(totalSat);

Here, you're trying to grab your cells of interest and then add them together to display them.

The problem is that you're using LookerCharts.Utils.htmlForCell, which takes in a cell name reference, like secondCell or firstCell in your example. When you feed it secondCell+firstCell (which, by the way, is probably going to be 'count_csatcount_dsat' in your case since you're adding the cell names, not the values), it is getting undefined since there is no cell called 'count_csatcountdsat'.

Solution (overly verbose for example purposes, not the best) would be to replace those lines with:

    var firstCell = firstRow[queryResponse.fields.measures[0].name];
    var secondCell =secondRow[queryResponse.fields.measures[1].name];
    var firstCellValue = Number(LookerCharts.Utils.textForCell(firstCell));
    var secondCellValue = Number(LookerCharts.Utils.textForCell(firstCell));

    var totalSat = firstCellValue+secondCellValue;

    // Insert the data into the page
    // This would be unstyled, you'd have to actually construct the HTML string if you wanted it styled
    this._textElement.innerHTML = totalSat;

Does that make sense? Happy to explain more. This: https://lookervisbuilder.com/ is a really great resource for testing Looker custom viz, I highly recommend it.