MS PowerPoint JavaScript API BETA - How can I insert a new slide with insertSlidesFromBase64(base64File, options)?

Question

I am experimenting with the JavaScript APIs in beta/preview for a MS PowerPoint Add-in. What I want to achieve is to insert a new slide from a base64-encoded .pttx file into the current document.

I would expect that this is possible with the insertSlidesFromBase64(base64File, options) method, which is documented here: PowerPoint API doc

I have included https://appsforoffice.microsoft.com/lib/beta/hosted/office.js in the Add-in

I am working on Mac OS 10.15.7

I have updated PowerPoint to the newest version in the Beta Channel. The PowerPoint Version is 16.44 (20111100).

Now, I am not quite sure if the beta API Methods are actually available in my environment. The bigger issue I am facing though is, that I don't know on which object I can call this method. I think the method should be available somewhere in the context of the current document/presentation?!?

I think a very simple example of how I can insert a "base64EncodedPptx" with insertSlidesFromBase64("base64EncodedPptx") would solve the problem.

Answer 1

Your Mac PowerPoint version should have the implementation of this API.

In terms of very simple usage, here are some code snipplets:

    await PowerPoint.run(async function(context) {
      context.presentation.insertSlidesFromBase64( base64EncodedPptxFileAsString );
      context.sync();
    });

    await PowerPoint.run(async function (context) {
      context.presentation.insertSlidesFromBase64( base64EncodedPptxFileAsString,
        {
          formatting: "UseDestinationTheme",
          targetSlideId: "257#",
          sourceSlideIds: ["257#3396654126", "258#"]
        });
      context.sync();
    });

From javascript side, you can use a file picker for example to get the base64 string: If you have this in HTML

    <form>
        <input type="file" id="file" />
    </form>

and this in the script:

$("#file").change(() => tryCatch(useInsertSlidesApi));

async function useInsertSlidesApi() {
  const myFile = <HTMLInputElement>document.getElementById("file");
  const reader = new FileReader();

  reader.onload = async (event) => {
    // strip off the metadata before the base64-encoded string
    const startIndex = reader.result.toString().indexOf("base64,");
    const copyBase64 = reader.result.toString().substr(startIndex + 7);

    await PowerPoint.run(async function(context) {
      context.presentation.insertSlidesFromBase64(copyBase64);
      context.sync();
    });
  };

  // read in the file as a data URL so we can parse the base64-encoded string
  reader.readAsDataURL(myFile.files[0]);
}

/** 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);
  }
}