So I'm in the process of developing an add-in for excel. I started with the template generated by visual studio (not yeomon, since generating with VS made debugging setup easier). So far I've got some taskpane stuff set up to authenticate with a remote server, but now I've hit a problem trying to get custom functions running. The documentation is focused on yeomon-generated projects, and I've done my best to translate, but I seem to be missing something.
So what I've done so far:
For the sake of proof-of-concepting, I'm sticking with trying to get the samples provided in the OfficeDev repo working (https://github.com/OfficeDev/Excel-Custom-Functions). I've added the functions.ts from the sample (https://github.com/OfficeDev/Excel-Custom-Functions/blob/master/src/functions/functions.ts) to a MyAddInWeb/Custom directory in my project. I manually copied over the Functions.json and the Functions.html file generated by building the sample,and pointed the JSON-URL, JS-URL, and HTML-URL in my manifest to the respective file paths, as well as added an ExtensionPoint xsi:type="CustomFunctions tag and pointed script/page/metadata tags to the same files. The relevant portion of my manifest looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<OfficeApp
xmlns="http://schemas.microsoft.com/office/appforoffice/1.1"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:bt="http://schemas.microsoft.com/office/officeappbasictypes/1.0"
xmlns:ov="http://schemas.microsoft.com/office/taskpaneappversionoverrides"
xsi:type="TaskPaneApp">
...
<!--Begin TaskPane Mode integration. This section is used if there are no VersionOverrides or if the Office client version does not support add-in commands. -->
<Hosts>
<Host Name="Workbook" />
</Hosts>
<DefaultSettings>
<SourceLocation DefaultValue="~remoteAppUrl/Home.html" />
</DefaultSettings>
<!-- End TaskPane Mode integration. -->
<Permissions>ReadWriteDocument</Permissions>
<!-- Begin Add-in Commands Mode integration. -->
<VersionOverrides xmlns="http://schemas.microsoft.com/office/taskpaneappversionoverrides" xsi:type="VersionOverridesV1_0">
<!-- The Hosts node is required. -->
<Hosts>
<!-- Each host can have a different set of commands. -->
<!-- Excel host is Workbook, Word host is Document, and PowerPoint host is Presentation. -->
<!-- Make sure the hosts you override match the hosts declared in the top section of the manifest. -->
<Host xsi:type="Workbook">
<!-- Form factor. Currently only DesktopFormFactor is supported. -->
<AllFormFactors>
<ExtensionPoint xsi:type="CustomFunctions">
<Script>
<SourceLocation resid="Functions.Script.Url"/>
</Script>
<Page>
<SourceLocation resid="Functions.Page.Url"/>
</Page>
<Metadata>
<SourceLocation resid="Functions.Metadata.Url"/>
</Metadata>
<Namespace resid="Functions.Namespace"/>
</ExtensionPoint>
</AllFormFactors>
<DesktopFormFactor>
...
</DesktopFormFactor>
</Host>
</Hosts>
<!-- You can use resources across hosts and form factors. -->
<Resources>
<bt:Images>
<bt:Image id="Contoso.tpicon_16x16" DefaultValue="~remoteAppUrl/Images/Button16x16.png" />
<bt:Image id="Contoso.tpicon_32x32" DefaultValue="~remoteAppUrl/Images/Button32x32.png" />
<bt:Image id="Contoso.tpicon_80x80" DefaultValue="~remoteAppUrl/Images/Button80x80.png" />
</bt:Images>
<bt:Urls>
<bt:Url id="JSON-URL" DefaultValue="~remoteAppUrl/Custom/Functions.json"/>
<bt:Url id="JS-URL" DefaultValue="~remoteAppUrl/Custom/Functions.js"/>
<bt:Url id="HTML-URL" DefaultValue="~remoteAppUrl/Custom/Functions.html"/>
<bt:Url id="Functions.Script.Url" DefaultValue="~remoteAppUrl/Custom/Functions.js" />
<bt:Url id="Functions.Metadata.Url" DefaultValue="~remoteAppUrl/Custom/Functions.json" />
<bt:Url id="Functions.Page.Url" DefaultValue="~remoteAppUrl/Custom/Functions.html" />
<bt:Url id="Contoso.DesktopFunctionFile.Url" DefaultValue="~remoteAppUrl/Functions/FunctionFile.html" />
<bt:Url id="Contoso.Taskpane.Url" DefaultValue="~remoteAppUrl/Home.html" />
<bt:Url id="Contoso.Callback.Url" DefaultValue="~remoteAppUrl/callback.html" />
<bt:Url id="Contoso.GetStarted.LearnMoreUrl" DefaultValue="https://go.microsoft.com/fwlink/?LinkId=276812" />
</bt:Urls>
<!-- ShortStrings max characters==125. -->
<bt:ShortStrings>
<bt:String id="Functions.Namespace" DefaultValue="CONTOSO" />
<bt:String id="Contoso.TaskpaneButton.Label" DefaultValue="Show Taskpane" />
<bt:String id="Contoso.Group1Label" DefaultValue="Commands Group" />
<bt:String id="Contoso.GetStarted.Title" DefaultValue="Get started with your sample add-in!" />
</bt:ShortStrings>
<!-- LongStrings max characters==250. -->
<bt:LongStrings>
<bt:String id="Contoso.TaskpaneButton.Tooltip" DefaultValue="Click to Show a Taskpane" />
<bt:String id="Contoso.GetStarted.Description" DefaultValue="Your sample add-in loaded succesfully. Go to the HOME tab and click the 'Show Taskpane' button to get started." />
</bt:LongStrings>
</Resources>
</VersionOverrides>
<!-- End Add-in Commands Mode integration. -->
</OfficeApp>
So here's where I hit the first hurdle. In Functions.ts, I got a typescript error complaining that CustomFunctions namespace is not defined. Not sure where that comes from in the sample. If I removed the type declaration (bad idea, I know), the add-in builds, and the custom functions show up are registered, but attempting to run any of them causes excel to hang on "We're starting the add-ins runtime, just a moment..." for a moment, and then I get an error in the task pane saying the add-in could not be started. Unfortunately, I'm not getting any usable error messages as far as I can see, so I'm not sure where the problem lies. If I had to guess, something isn't hooked up correctly in the manifest, but I'm not sure. Any help would be much appreciated. The documentation so far seems pretty lacking.