This sample shows how to set a cell value to an error data type, and then update the value of a cell that contains an error data type.

Data types: Set and change error values.EXCEL.yaml

name: 'Data types: Set and change error values'
description: >-
  This sample shows how to set a cell value to an error data type, and then
  update the value of a cell that contains an error data type.
host: EXCEL
api_set: {}
script:
  content: |
    $("#setup").click(() => tryCatch(setup));
    $("#set-busy-error").click(() => tryCatch(setBusyError));
    $("#change-busy-error").click(() => tryCatch(changeBusyError));

    async function setBusyError() {
      // This function sets the value of cell A1 to a #BUSY! error using data types.
      await Excel.run(async (context) => {
        // Retrieve the Sample worksheet and cell A1 on that sheet.
        const sheet = context.workbook.worksheets.getItemOrNullObject("Sample");
        const range = sheet.getRange("A1");

        // Get the error data type and set its type to `busy`.
        const error: Excel.ErrorCellValue = {
          type: Excel.CellValueType.error,
          errorType: Excel.ErrorCellValueType.busy
        };

        // Set cell A1 as the busy error.
        range.valuesAsJson = [[error]];
        await context.sync();
      });
    }

    async function changeBusyError() {
      // This function checks if a range contains a #BUSY! error, and then updates the range if it contains the error.
      await Excel.run(async (context) => {
        // Retrieve the Sample worksheet and cell A1 on that sheet.
        const sheet = context.workbook.worksheets.getItemOrNullObject("Sample");
        const range = sheet.getRange("A1");

        // Load the `valuesAsJson` property for comparison.
        range.load("valuesAsJson");
        await context.sync();

        // Check if the range contains a #BUSY! error.
        if (range.valuesAsJson[0][0]["errorType"] == Excel.ErrorCellValueType.busy) {
          // If the range contains a #BUSY! error, load and change the value of the range.
          range.load("values");
          await context.sync();
          range.values = [["Process unavailable."]];
        }

        await context.sync();
      });
    }

    async function setup() {
      await Excel.run(async (context) => {
        // Create a new worksheet called "Sample" and activate it.
        context.workbook.worksheets.getItemOrNullObject("Sample").delete();
        const sheet = context.workbook.worksheets.add("Sample");
        sheet.activate();

        await context.sync();
      });
    }

    /** Default helper for invoking an action and handling errors. */
    async function tryCatch(callback) {
      try {
        await callback();
      } catch (error) {
        // Note: In a production add-in, you'd want to notify the user through your add-in's UI.
        console.error(error);
      }
    }
  language: typescript
template:
  content: "<section class=\"ms-font-m\">\n\t<p>This sample shows how to set the value of cell A1 to the #BUSY! error data type. The sample then checks to see if\n\t\tcell A1 contains a #BUSY! error, and updates the cell value if it does.</p>\n</section>\n<section class=\"setup ms-font-m\">\n\t<h3>Set up</h3>\n\t<button id=\"setup\" class=\"ms-Button\">\n    <span class=\"ms-Button-label\">Add worksheet</span>\n  </button>\n\t<h3>Try it out</h3>\n\t<button id=\"set-busy-error\" class=\"ms-Button\">\n    <span class=\"ms-Button-label\">Set A1 to #BUSY! error</span>\n  </button>\n\t<button id=\"change-busy-error\" class=\"ms-Button\">\n    <span class=\"ms-Button-label\">Change output of cell with #BUSY! error</span>\n  </button>\n</section>"
  language: html
style:
  content: |-
    section.samples {
        margin-top: 20px;
    }

    section.samples .ms-Button, section.setup .ms-Button {
        display: block;
        margin-bottom: 5px;
        margin-left: 20px;
        min-width: 80px;
    }
  language: css
libraries: |
  https://appsforoffice.microsoft.com/lib/1/hosted/office.js
  @types/office-js

  office-ui-fabric-js@1.4.0/dist/css/fabric.min.css
  office-ui-fabric-js@1.4.0/dist/css/fabric.components.min.css

  core-js@2.4.1/client/core.min.js
  @types/core-js

  jquery@3.1.1
  @types/jquery@3.3.1