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    Office JavaScript APIs

    The JavaScript API for Office enables you to create web applications that interact with the object models in Office host applications. Your application will reference the office.js library, which is a script loader. The office.js library loads the object models applicable to the Office application running the add-in.

    About the NPM package

    The NPM package for Office.js is a copy of what gets published to the official "evergreen" Office.js CDN, at

    The Office.js CDN contains all currently available Office.js APIs at any moment in time.

    Each Office.js NPM package contains only Office.js APIs available on the Office.js CDN when the NPM package version was created.

    Target scenarios

    The NPM package for Office.js is intended as a way to obtain an offline copy (non-CDN) of the Office.js files, which can then be statically serve from your own site instead of using the CDN.

    This NPM package is provided for the following scenarios:

    1. Development of an Add-in behind a firewall, when accessing the Office.js CDN is not possible.
    2. Offline access to the Office.js APIs to facilitate offline debugging.

    Important: Office Add-ins published to AppSource must use the CDN reference. Offline Office.js references are only appropriate for internal development, and debugging scenarios.

    Best practices

    Best practices for using the Office.js NPM package include:


    The Office.js CDN is the official supported source for Office Add-ins.

    For the NPM package sourced through this repository, only the latest version of the package is supported. No support and no patches will be provided for previous versions of the package. The frequency of the updates to this repository and related NPM package to match the CDN version is not guaranteed.

    Outlook add-ins do not support hosting Office.js offline due to network access requirements for dependencies like the Microsoft Ajax library.

    Install the NPM package

    To install "office-js" locally via the NPM package, run the following command:

    npm install @microsoft/office-js --save

    Our policy requires that developers always reference the latest version of Office.js library. This is to ensure that essential product updates are served quickly to the Office Add-ins by always referencing the latest release of the library for a given version, such as Generally Available (GA) version. Given that the latest Office.js release is backward-compatible with prior releases, it is safe to update to the most recent release of the library when one is available. Hence, only the latest version of Office.js NPM package is made available for installation.

    Use the NPM package

    Installing the NPM package locally creates a set of static Office.js files in the node_modules\@microsoft\office-js\dist folder of the directory where you ran the npm install command. To use the NPM package, do the following:

    1. Either manually or as part of a build script (e.g., CopyWebpackPlugin if you're using Webpack) have the files served from a destination of your choosing (e.g., from the /assets/office-js/ directory of your web server).

    2. Reference that location in a <script> tag within the HTML file in your add-in project.

    For example, if you add the contents of the dist folder to the assets/office-js directory of your project, then you'd add the following <script> tag to your HTML file:

    <script src="/assets/office-js/office.js"></script>

    IntelliSense definitions

    TypeScript definitions for Office.js are available.

    Use TypeScript definitions with the NPM package

    If you're using the Office.js NPM package for the firewall scenario and want a d.ts file that precisely matches the JS contents, use the d.ts file that is located within the /dist/office.d.ts folder of the NPM package. Achieve this by using a triple-slash reference.

    • TIP: If you create a references.ts file at the root of the project, simply point the reference to office.d.ts there.

    If you don't need the firewall scenario, don't use the Office.js NPM package, obtain the TypeScript definitions by using @types/office-js and reference the Office.js CDN at

    Enable IntelliSense in Visual Studio

    Visual Studio 2017+ can use these same TypeScript definitions, even for regular JavaScript. For JavaScript IntelliSense in earlier versions of Visual Studio, an office-vsdoc.js is available alongside the office.js file. As long as you have a Scripts/_references.js file in your VS project, and as long as you substitute the existing triple-slash reference (/// <reference path="https://.../office.js" />) with the new location (the -vsdoc part gets substituted automatically, so use it just as you would in a <script src=""> reference), you should have the corresponding JavaScript IntelliSense.

    NPM Package Versions

    Office.js versioning is described in detail in Importantly, there is a difference between what is in the JS files, versus what are the capabilities of a particular computer (i.e., older or slower-to-update versions of office).

    The NPM package and the repo branches assume the following structure.

    GitHub branch name NPM tag name Description
    release latest Identical to a previous release on

    The latest released publicly-available APIs.
    beta beta Identical to a previous release on

    Forthcoming APIs, not necessarily ready for public consumption that may change. Possibly available on Insider Fast (and maybe Insider Slow) builds.

    Code of Conduct

    This project has adopted the Microsoft Open Source Code of Conduct. For more information, see the Code of Conduct FAQ or contact with any additional questions or comments.

    More info

    For more information on Office Add-ins and the Office JavaScript APIs, see:

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