This program will select a range of cells and perform some formatting.

MyFirstJavaScript Program.EXCEL.yaml

name: MyFirstJavaScript Program
description: This program will select a range of cells and perform some formatting.
host: EXCEL
api_set: {}
script:
  content: |
    /*
     * let's assign a function to our run button
     * in this case on the 'Click' event we will
     * execute our 'Run' function and wrap it in our
     * tryCatch function so that way any errors that
     * are caught are notified to us.
     */
    $("#run").click(() => tryCatch(highlightCell));

    /** Default helper for invoking an action and handling errors. */
    async function tryCatch(callback) {
      try {
        await callback();
      } catch (error) {
        OfficeHelpers.UI.notify(error);
        OfficeHelpers.Utilities.log(error);
      }
    }

    async function highlightCell() {
      await Excel.run(async (context) => {
        /* Grab the selected Range */
        var selectedRange = context.workbook.getSelectedRange();

        /* set the fill color to blue */
        selectedRange.format.fill.color = "#4472C4";

        /* set the font color to white */
        selectedRange.format.font.color = "white";

        /* autofit the columns */
        selectedRange.format.autofitColumns();
      });
    }
  language: typescript
template:
  content: |
    <button id="run" class="ms-Button">
        <span class="ms-Button-label">Run</span>
    </button>
  language: html
style:
  content: |
    /* Your style goes here */
  language: css
libraries: |
  https://appsforoffice.microsoft.com/lib/1/hosted/office.js
  @types/office-js

  [email protected]/dist/css/fabric.min.css
  [email protected]/dist/css/fabric.components.min.css

  [email protected]/client/core.min.js
  @types/core-js

  @microsoft/[email protected]/dist/office.helpers.min.js
  @microsoft/[email protected]/dist/office.helpers.d.ts

  [email protected]
  @types/[email protected]